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{{short description|Penetrative sexual activity for reproduction or sexual pleasure}}
{{redirect|Intromission|the intromission theory of visual perception|Intromission theory}}
{{hatnote|This article is primarily about humans. For other animals, see ]. For other uses, see ].}}
{{redirect|Making love}}
{{redirect|Copulation|copulation among other animals|Copulation (zoology)|the biological functions of sexual intercourse|Penile-vaginal intercourse}}
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] of human sexual intercourse depicted by ]]]
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]s copulating in the ], ]]]
] depicted by ] (1892)|220x220px]]
'''Sexual intercourse''' (also '''coitus''' or '''copulation'''<!-- NOTE: "Sex" is not bolded as an alternative term. This is per WP:Alternative name and MOS:BOLD. It does not redirect here, and is mentioned lower in the lead. It is also a significantly broader term.
-->) is a ]<!-- NOTE: To align with WP:Due weight, the most common definition has been put forth first. "Coitus" and "copulation," which are the most common technical terms for sexual intercourse, are also being defined in the first sentence (for both humans and non-humans) and these terms, especially coitus, usually only mean penile–vaginal intercourse, as reported in various reliable sources (including those used to discuss the topic in the Definitions section below). The variant "sexual intercourse" is slightly more inclusive, but is additionally addressed in most sources and in the Definitions and Prevalence sections as most commonly meaning penile–vaginal intercourse.--> typically involving the insertion and ] of the male ] inside the female ] for ], ], or both.<ref name="Most common">Sexual intercourse most commonly means penile–vaginal penetration for sexual pleasure or sexual reproduction; dictionary sources state that it especially means this, and scholarly sources over the years agree. See, for example;
* {{cite dictionary |title=Sexual intercourse |dictionary=] |url=https://www.dictionary.com/browse/sexual-intercourse |access-date=August 24, 2024}}
* {{cite dictionary |title=Sexual intercourse |dictionary=] |url=http://www.merriam-webster.com/dictionary/sexual%20intercourse |access-date=August 24, 2024}}
* {{cite book |author=Richard M. Lerner |url=https://books.google.com/books?id=_wXasY1HyAYC&pg=PA193 |title=Handbook of Adolescent Psychology |author2=Laurence Steinberg |publisher=] |year=2004 |isbn=978-0-471-69044-3 |pages=193–196 |quote=When researchers use the term ''sex'', they nearly always mean sexual intercourse&nbsp;– more specifically, penile–vaginal intercourse. The widespread, unquestioned equation of penile–vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question matches what the researcher had in mind.' |author-link=Richard M. Lerner |author2-link=Laurence Steinberg |access-date=April 29, 2013}}
* {{cite book |author=Fedwa Malti-Douglas |author-link=Fedwa Malti-Douglas |url=https://archive.org/details/encyclopediaofse0000unse_i6t7 |title=Encyclopedia of Sex and Gender: A-C |publisher=] |year=2007 |isbn=978-0-02-865961-9 |page=308 |quote=Sexual intercourse. he term coitus indicates a specific act of sexual intercourse that also is known as coition or copulation. This 'coming together' is generally understood in heteronormative terms as the penetration of a woman's vagina by a man's penis. |url-access=registration}}
* {{cite book |author=Irving B. Weiner |url=https://books.google.com/books?id=pUSG1BONmekC&pg=PA1577 |title=The Corsini Encyclopedia of Psychology |author2=W. Edward Craighead |publisher=] |year=2010 |isbn=978-0-470-17023-6 |volume=4 |page=1577 |quote=Human sexual intercourse, or coitus, is one of the most common sexual outlets among adults. Sexual intercourse generally refers to penile penetration of the vagina. |author-link=Irving B. Weiner |access-date=August 21, 2013}}
* {{cite book |author=Clint E. Bruess |url=https://books.google.com/books?id=WWFW6-kkAVoC&pg=PA152 |title=Sexuality Education Theory and Practice |author2=Elizabeth Schroeder |publisher=] |year=2013 |isbn=978-1-4496-4928-9 |page=152 |quote=In many cultures around the world, vaginal sex is what is usually implied when people refer to 'having sex' or 'sexual intercourse.' It is the most frequently studied behavior and is often the focus of sexuality education programming for youth. |access-date=December 5, 2014}}
* {{cite book |author=Cecie Starr |url=https://books.google.com/books?id=lS5-BAAAQBAJ&pg=PT339 |title=Human Biology |author2=Beverly McMillan |publisher=] |year=2015 |isbn=978-1-305-44594-9 |page=339 |quote=Coitus and copulation are both technical terms for sexual intercourse. The male sex act involves an erection, in which the limp penis stiffens and lengthens. It also involves ejaculation, the forceful expulsion of semen into the urethra and out from the penis. During coitus, pelvic thrusts stimulate the penis as well as the female's clitoris and vaginal wall. The stimulation triggers rhythmic, involuntary contractions in smooth muscle in the male reproductive tract, especially the vas deferens and the prostate. The contractions rapidly force sperm out of each epididymis. They also force the contents of seminal vesicles and the prostate gland into the urethra. The resulting mixture, semen, is ejaculated into the vagina. |access-date=December 27, 2017}}
* {{cite book |author=Janell L. Carroll |url=https://books.google.com/books?id=9A9EDwAAQBAJ&pg=PT289 |title=Sexuality Now: Embracing Diversity |publisher=] |year=2018 |isbn=978-1-337-67206-1 |page=289 |quote=Vaginal intercourse (also referred to as sexual intercourse) involves inserting the penis into the vagina. |access-date=November 22, 2019}}</ref> This is also known as '''vaginal intercourse''' or '''vaginal sex'''.<ref name="Alters">{{cite book| vauthors =Alters S| title = Essential Concepts for Healthy Living | publisher = ] | year = 2012 | pages = 180–181|isbn = 978-1-4496-3062-1 | url=https://books.google.com/books?id=VegUiVbruBMC&pg=PA180|quote=Most heterosexuals are familiar with the notion of 'having sex' or sexual intercourse as vaginal sex, the insertion of a penis into a vagina. Vaginal sex, or coitus, is the most common and popular form of intimate sexual activity between partners.}}</ref><ref name="Carroll, 2018">{{cite book| vauthors = Carroll JL|title = Sexuality Now: Embracing Diversity| publisher = ]| year = 2018 | page = 289|isbn = 978-1-337-67206-1| url =https://books.google.com/books?id=9A9EDwAAQBAJ&pg=PT289|quote=Vaginal intercourse (also referred to as sexual intercourse) involves inserting the penis into the vagina.}}</ref> Sexual penetration has been known by humans since the dawn of time, and has been an ] form of ] and ] among humans. Other forms of ] sexual intercourse include ] (penetration of the ] by the penis), ] (penetration of the mouth by the penis or oral penetration of the female ]), ] (sexual penetration by the fingers) and penetration by use of a ] (especially a ]), and ].<ref name="health.discovery.com">{{cite web |title=Sexual Intercourse |url=http://health.discovery.com/centers/sex/sexpedia/intercourse.html |archive-url=https://web.archive.org/web/20080822040701/http://health.discovery.com/centers/sex/sexpedia/intercourse.html |archive-date=August 22, 2008 |access-date=January 12, 2008 |publisher=]}}</ref><ref name="Rathus">{{Cite book |url=https://archive.org/details/humansexualityin00rath_1 |title=Human Sexuality in a World of Diversity |vauthors=Rathus SA, Nevid JS, Rathus LF |publisher=] |year=2010 |isbn=978-0-205-78606-0 |page=251 |url-access=registration}}</ref> These activities involve ] between two or more people and are usually used among humans solely for physical or ] pleasure. They can contribute to ].<ref name=health.discovery.com/><ref name="Freberg">{{Cite book |url=https://archive.org/details/discoveringbiolo0002edfreb |title=Discovering Biological Psychology |vauthors=Freberg L |publisher=] |year=2009 |isbn=978-0-547-17779-3 |pages=308–310 |url-access=registration}}</ref>


There are different views on what constitutes sexual intercourse or other sexual activity, which can impact on views of ].<ref name="WHO, Sex">{{cite web |date=January 2002 |title=Defining sexual health: Report of a technical consultation on sexual health |url=https://www.who.int/reproductivehealth/topics/gender_rights/defining_sexual_health.pdf |archive-url=https://web.archive.org/web/20120906205203/https://www.who.int/reproductivehealth/topics/gender_rights/defining_sexual_health.pdf |archive-date=September 6, 2012 |access-date=September 5, 2012 |publisher=] |page=4 |quote=In English, the term 'sex' is often used to mean 'sexual activity' and can cover a range of behaviours. Other languages and cultures use different terms, with slightly different meanings.}}</ref> Although ''sexual intercourse'', particularly the term ''coitus,'' generally denotes penile–vaginal penetration and the possibility of creating ],<ref name="Most common"/> it also commonly denotes penetrative oral sex and penile–anal sex, especially the latter.<ref name="Oral and anal">* {{cite web |title=Sexual Intercourse |url=http://health.discovery.com/centers/sex/sexpedia/intercourse.html |archive-url=https://web.archive.org/web/20080822040701/http://health.discovery.com/centers/sex/sexpedia/intercourse.html |archive-date=August 22, 2008 |access-date=January 12, 2008 |publisher=]}}
'''Sexual intercourse''', also known as '''copulation''' or '''coitus''', commonly refers to the act in which the ] enters the ].<ref> ] entry.</ref><ref name="health.discovery.com">{{cite web | author= | title= Sexual Intercourse | publisher=health.discovery.com | accessdate=2008-01-12 | url=http://health.discovery.com/centers/sex/sexpedia/intercourse.html}}</ref> The two entities may be of opposite ]es or not, or they may be ], as is the case with ]s. In recent years, penetration of non-] (], ]) or by non-sexual organs (], ]) are also sometimes included in this definition.<ref name=health.discovery.com/> Traditionally, intercourse has been viewed as the natural endpoint of all sexual contact between a man and a woman.<ref name=health.discovery.com/>
* {{cite book |author=Nancy W. Denney |url=https://archive.org/details/humansexuality0000denn_r0k2 |title=Human Sexuality |author2=David Quadagno |publisher=] |year=2008 |isbn=978-0-8016-6374-1 |page=273 |quote=Although the term intercourse is usually used to refer to the insertion of the penis into the vagina, it is also used to refer to oral intercourse or anal intercourse in which the penis is inserted into the mouth or the anus, respectively. |url-access=registration}}</ref> It usually encompasses sexual penetration, while ] has been labeled ''outercourse'',<ref name="Non-penetrative">
* {{Cite book| author = Ann O'Leary |author-link=Ann O'Leary (psychologist) | title =Beyond Condoms: Alternative Approaches to HIV Prevention| isbn = 978-0-306-46731-8| publisher = ] | year = 2002|page =155|url=https://books.google.com/books?id=J3NT39hW474C&pg=PA155}}
* {{cite book|author=Dianne Hales|title=An Invitation to Health: Live It Now! Brief Edition|edition=3rd|isbn = 978-1-305-44595-6|publisher=]|year=2015|page=251|url=https://books.google.com/books?id=UTJBBAAAQBAJ&pg=PT251}}</ref> but non-penetrative sex may also be considered sexual intercourse.<ref name=health.discovery.com/><ref name="Kahn, Fawcett">{{cite book |url=https://archive.org/details/encyclopediaofme0000kahn |title=The Encyclopedia of Mental Health |vauthors=Kahn AP, Fawcett J |publisher=] |year=2008 |isbn=978-0-8160-6454-0 |page=111 |url-access=registration}}</ref> ''Sex'', often a shorthand for ''sexual intercourse'', can mean any form of sexual activity.<ref name="WHO, Sex"/> Because people can be at risk of contracting ] during these activities, ] practices are recommended by health professionals to reduce transmission risk.<ref name="Hales">{{Cite book |url=https://archive.org/details/invitationtoheal00hale_3 |title=An Invitation to Health Brief 2010–2011 |vauthors=Hales D |publisher=] |year=2008 |isbn=978-0-495-39192-0 |pages=269–271 |url-access=registration}}</ref><ref name="Kumar">{{Cite book|vauthors=Kumar B, Gupta S|title=Sexually Transmitted Infections| publisher = ]|year = 2014|page=93|isbn = 978-81-312-2978-1|url=https://books.google.com/books?id=kQ9tAwAAQBAJ&pg=PA93}}</ref>


Various jurisdictions place restrictions on certain sexual acts, such as ], ], sexual activity with ], ], ], ], ], ] and ]. ] beliefs also play a role in personal decisions about sexual intercourse or other sexual activity, such as decisions about ],<ref name="Carpenter"/><ref name="Intimate">{{Cite book |url=https://archive.org/details/marriagefamilyex00 |title=The Marriage and Family Experience: Intimate Relationship in a Changing Society |vauthors=Strong B, DeVault C, Cohen TF |publisher=] |year=2010 |isbn=978-0-534-62425-5 |page=186 |quote=Most people agree that we maintain virginity as long as we refrain from sexual (vaginal) intercourse. But occasionally we hear people speak of 'technical virginity' Data indicate that 'a very significant proportion of teens ha had experience with oral sex, even if they haven't had sexual intercourse, and may think of themselves as virgins' Other research, especially research looking into virginity loss, reports that 35% of virgins, defined as people who have never engaged in vaginal intercourse, have nonetheless engaged in one or more other forms of heterosexual sexual activity (e.g., oral sex, anal sex, or mutual masturbation). |access-date=October 8, 2011 |url-access=registration}}</ref> or legal and public policy matters. ] vary significantly between different religions and sects of the same religion, though there are common themes, such as prohibition of adultery.
] (oral sex may or may not be penetrative) and mutual masturbation have been referred to as "outercourse".<ref name="books.google.com">
{{cite book | author = Kate Havelin | title = | isbn = 0736802924 | publisher = Capstone Press | year = 1999 |pages = 64}}</ref><ref name="Books.google.com">
{{cite book | author = Isadora Alman | title = | isbn = 1573245208 | publisher = Conari
| year = 2001 |pages = 280}}</ref><ref name="BOoks.google.com">
{{cite book | author = Ann van Sevenant| title = | isbn = 9042916176 | publisher = Peeters | year = 2005 |pages = 249}}</ref><ref name="BOOks.google.com">
{{cite book | author = Ian Kerner | title = | isbn = 1573245208 | publisher = HarperCollins | year = 2004 |pages = 240}}</ref> "Outercourse" is something of a misnomer, as it contrasts "outer" with "inter" but the "inter" in "intercourse" means "between two people" or beings. It does not describe being inside or outside of the body. The word '''sex''', in the context of sexual intimacy, is often, if not universally, understood to include any mutual ] stimulation, i.e. both intercourse and outercourse.<ref name="www.ejhs.org">{{cite web |first=Marty| last=Klein | title=The Meaning of Sex|publisher=Electronic Journal of Human Sexuality, Volume 1 August 10, 1998:|accessdate=2007-12-09|url=http://www.ejhs.org/volume1/mklein.htm}}</ref>


Reproductive sexual intercourse between non-human animals is more often called '']'', and ] may be introduced into the female's reproductive tract in non-vaginal ways among the animals, such as by ]l copulation. For most non-human ]s, ] and copulation occur at the point of ] (the most fertile period of time in the female's reproductive cycle), which increases the chances of ].<ref name="Kent">{{Cite book| author =Michael Kent| title = Advanced biology| isbn = 978-0-19-914195-1| publisher = ] | year = 2000 |pages =250–253|url=https://books.google.com/books?id=8aw4ZWLABQkC&pg=PA250|access-date=October 21, 2015}}</ref><ref name="Thorpe">{{Cite book| author = Showick Thorpe| author2 = Edgar Thorpe | title = The Pearson General Studies Manual 2009, 1/e | publisher = ]| year = 2009 |page = 1.79 | isbn =978-81-317-2133-9 |url=https://books.google.com/books?id=oAo1X2eagywC&pg=RA1-PR17|access-date=October 21, 2015}}</ref> However, ]s, ]s and ] are known to engage in sexual intercourse regardless of whether the female is in estrus, and to engage in ].<ref name="Non-human">
] is the term most often used to refer to sexual intercourse between animals other than humans; for most, mating occurs at the point of ] (the most fertile period of time in the female's reproductive cycle),<ref name="BOOKs.google.com">"Females of almost all species except man will mate only during their fertile period, which is known as ], or heat..." {{cite book | author = Helena Curtis| title =Biology | isbn = 0879010401 | publisher = Worth Publishers | year = 1975 |pages =1065 }}</ref><ref name="BOOKS.google.com">
* {{Cite book|author1=Herbert L. Petri |author2=John M. Govern| title = Motivation: Theory, Research, and Application| year = 2012 | publisher = ] |page= 24 | isbn = 978-1-285-40151-5 |url=https://books.google.com/books?id=DbwKAAAAQBAJ&pg=PA24}}
{{cite book | author =Pineda, Leslie Ernest McDonald | title = | isbn = 0813811066 | publisher = Blackwell Publishing| year = 2003 |pages =597 }}</ref> which increases the chances of ]. However, ]s,<ref>], "Bonobo Sex and Society", ''Scientific American'' (March 1995): 82-86.</ref> ]s,<ref name=Dinitia/> and ]s are known to engage in sexual intercourse even when the female is not in estrus, and to engage in sex acts with same-sex partners.<ref name="Bagemihl">Bruce Bagemihl, ''Biological Exuberance: Animal Homosexuality and Natural Diversity'' (St. Martin's Press, 1999). ISBN 0-312-19239-8</ref> In most instances, humans have sex primarily for pleasure.<ref name="Diamond">{{cite book | author = Jared Diamond | title = The rise and fall of the third chimpanzee| year = 1992 | publisher = Vintage | isbn = 978-0099913801}}</ref> This behavior in the above mentioned animals is also presumed to be for pleasure,<ref name="wired.com">{{cite web| first=Gartner| last=John | title=Animals Just Want to Have Fun |publisher='']''|date=2006-08-15 |accessdate=2007-10-15|url=http://www.wired.com/culture/culturereviews/news/2006/08/71556}}</ref> which in turn strengthens social bonds.
* {{cite journal |vauthors=Bailey NW, Zuk M | title = Same-sex sexual behavior and evolution | journal = Trends Ecol. Evol. | volume = 24 | issue = 8 | pages = 439–46 | date = August 2009 | pmid = 19539396 | doi = 10.1016/j.tree.2009.03.014 | bibcode = 2009TEcoE..24..439B | issn=0169-5347}}</ref> Like humans engaging in sexual activity primarily for pleasure, this behavior in these animals is also presumed to be for pleasure, and a contributing factor to strengthening their social bonds.<ref name="Balcombe">{{Cite book|last=Balcombe|first=Jonathan|author-link= Jonathan Balcombe | title = Pleasurable Kingdom: Animals and the Nature of Feeling Good| year = 2006 |publisher = ] |pages= –118 | isbn = 978-0-230-55227-2|url=https://archive.org/details/pleasurablekingd00balc_0|url-access=registration}}</ref>
{{TOC limit|3}}


==Behaviors==
]s view sexual intercouse between husband and wife as a spiritual and edifying action, while extra-marital sex is viewed as immoral. The teachings of ] and ] on sexuality have differing interpretations. Buddhism's injunction to "refrain from sexual misconduct" is not well defined. Modern ] philosophy and theology view marital sexual love as the best image of ] who is love, as they see the human body as the only one capable of making the invisible &mdash; the spiritual and the divine &mdash; visible.<ref>Karol Woytyla, Love and Responsibility, San Francisco, Ignatius Press 1993</ref><ref>Theology of Marriage and Celibacy, Boston, St. Paul Books and Media 1986</ref>
{{See also|Human sexual activity|Human sexuality}}


== In animals == ===Definitions===
]]]
{{See also|Mating}}
] interpretation of Roman emperor ] and ] engaged in anal intercourse, by ]]]
]s mating]]
<!-- NOTE: This section was titled "Etymology and definitions." As the etymology material is defining sexual intercourse, and there is little material on the etymology, there appears to be no need to have separate sections. Per MOS:PARAGRAPHS, "Short paragraphs and single sentences generally do not warrant their own subheading." The heading was subsequently shortened to "Definitions" and added as a subsection of the Behaviors section (since it includes researchers' views and general views on definitions and behaviors).-->


''Sexual intercourse'' may be called ''coitus'', ''copulation'', ''coition'', or ''intercourse''. ''Coitus'' is derived from the ] word ''coitio'' or ''coire'', meaning "a coming together or joining together" or "to go together", and is known under different ancient Latin names for a variety of sexual activities, but usually denotes penile–vaginal penetration.<ref name="Coitus">
Many animals which live in the water use ], whereas ] may have developed from a need to maintain ]s in a liquid medium in the ] epoch. Internal fertilization with many vertebrates (such as ]s, some ], and most ]s) occur via ]l copulation (see also ]), while ]s copulate ]lly, and many ] ]s reproduce sexually with external fertilization.
* {{cite dictionary|title=Coitus| date=August 14, 2024| dictionary=]|url=http://www.merriam-webster.com/dictionary/coitus}}
* {{cite book| author = Fedwa Malti-Douglas |author-link=Fedwa Malti-Douglas |title = Encyclopedia of Sex and Gender: A-C |publisher = ] | year = 2007 | page = 308 |isbn = 978-0-02-865961-9 |quote=Sexual intercourse. he term coitus indicates a specific act of sexual intercourse that also is known as coition or copulation. This 'coming together' is generally understood in heteronormative terms as the penetration of a woman's vagina by a man's penis.}}
* {{cite book|title = The Encyclopedia of Mental Health | publisher = ] | year = 2008 | page = 111|isbn = 978-0-8160-6454-0| url = https://books.google.com/books?id=tTFYIh-HcYYC&pg=PA111|author1=Ada P. Kahn |author2=Jan Fawcett }}
</ref> This is often called ] or ''vaginal sex.''<ref name="Alters"/><ref name="Carroll">See for orgasm information, and for definitions, prevalence and length of sexual intercourse. {{cite book |vauthors=Carroll JL| title = Discovery Series: Human Sexuality| edition = 1st | publisher = ]|pages=656 pages| isbn = 978-1-111-84189-8|year=2012|url=https://books.google.com/books?id=gU3SZSh-eXsC}}</ref> ''Vaginal sex,'' and less often ''vaginal intercourse'', may also denote any vaginal sexual activity, particularly if ], including ].<ref name="Harvey">{{cite book|vauthors = Milkman HB, Wanberg KW | title = Pathways to Self-Discovery and Change: Criminal Conduct and Substance Abuse Treatment for Adolescents | publisher = ] | year = 2004 | pages = 254–255|isbn = 978-1-4129-0614-2| url =https://books.google.com/books?id=2ovqg5jfsN0C&pg=PA254}}</ref><ref name="Kinetics">{{cite book| vauthors = Kinetics H | title = Health and Wellness for Life| publisher = Human Kinetics | year = 2009 | page = 207|isbn = 978-0-7360-6850-5| url =https://books.google.com/books?id=2GZ7N4wOeGYC&pg=PA207}}</ref> ''Copulation'', by contrast, more often denotes the ] process, especially for non-human animals; it can mean a variety of sexual activities between opposite-sex or ],<ref name="Barrows">{{cite book| vauthors = Barrows EM| title = Animal Behavior Desk Reference: A Dictionary of Animal Behavior, Ecology, and Evolution | publisher = ] | year = 2011 | pages = 122–124 |isbn = 978-1-4398-3651-4 | url=https://books.google.com/books?id=2vf7ZbLENzEC&pg=PA122}}</ref> but generally means the ] act of transferring ] from a male to a female or sexual procreation between a man and a woman.<ref name="Barrows"/><ref name="Copulation1">{{cite web|title=Copulation|publisher=], 2007/] for various dictionary definitions|access-date=September 6, 2012|url=http://medical-dictionary.thefreedictionary.com/copulation}}</ref><ref name="Copulation2">{{cite web|title=Copulation|publisher=], Fifth Edition|year=2011|access-date=August 23, 2013|url=http://ahdictionary.com/word/search.html?q=Copulation}}</ref>


Although ''sex'' and ''having sex'' also most commonly denote penile–vaginal intercourse,<ref name="Most common2">
However, some ] ]s do use external fertilization. For primitive ]s, the male deposits ] on the substrate, sometimes stored within a special structure, and ] involves inducing the female to take up the sperm package into her genital opening; there is no actual copulation. In groups such as ] and ]s, males extrude sperm into secondary copulatory structures removed from their genital opening, which are then used to inseminate the female (in dragonflies, it is a set of modified ]s on the second abdominal segment; in spiders, it is the male ]s). In advanced groups of insects, the male uses its ], a structure formed from the terminal segments of the abdomen, to deposit sperm directly (though sometimes in a capsule called a "]") into the female's reproductive tract.
* {{cite book| author = Ken Plummer | author-link = Ken Plummer (sociologist) | title = Modern Homosexualities: Fragments of Lesbian and Gay Experiences | publisher = ] | year = 2002 | pages = 187–191 | access-date = August 24, 2013|isbn =978-1-134-92242-0 | url=https://books.google.com/books?id=OSO3q4XEfz4C&pg=PA189|quote=ome sexual practices are regarded as inherently better (normal, natural, more satisfying) than others, with vaginal intercourse privileged as the 'Real Thing.' Such beliefs, influenced by views about sex as ultimately a reproductive function, continue to be perpetuated through discourses on sex despite a number of important contradictions.}}
* {{cite book | title = Handbook of Adolescent Psychology | publisher = ] | year = 2004 | pages = 193–196 |isbn = 978-0-471-69044-3| url = https://books.google.com/books?id=_wXasY1HyAYC&pg=PA193|quote=When researchers use the term ''sex'', they nearly always mean sexual intercourse&nbsp;– more specifically, penile–vaginal intercourse... The widespread, unquestioned equation of penile–vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question matches what the researcher had in mind.'| author = Richard M. Lerner| author-link = Richard M. Lerner| author2 = Laurence Steinberg| author2-link = Laurence Steinberg}}
* See and for views on what constitutes virginity loss and therefore sexual intercourse or other sexual activity; source discusses how gay and lesbian individuals define virginity loss, and how the majority of researchers and heterosexuals define virginity loss/"technical virginity" by whether a person has engaged in penile–vaginal sex. {{Cite book|author=Laura M. Carpenter|title=Virginity Lost: An Intimate Portrait of First Sexual Experiences|publisher=]|year = 2005|pages=295 pages |isbn=978-0-8147-1652-6|url=https://books.google.com/books?id=pXXZn_qSoDoC}}
* {{cite book| author = Fedwa Malti-Douglas|title = Encyclopedia of Sex and Gender: A-C| publisher = ] | year = 2007 | page = 308 |isbn = 978-0-02-865961-9|quote=Sexual intercourse. he term coitus indicates a specific act of sexual intercourse that also is known as coition or copulation. This 'coming together' is generally understood in heteronormative terms as the penetration of a woman's vagina by a man's penis.}}
* {{cite book |author=Irving B. Weiner |author1-link=Irving B. Weiner |author2=W. Edward Craighead |title=The Corsini Encyclopedia of Psychology |volume=4 |publisher=] |year=2010 |page=1577 |access-date=August 21, 2013 |isbn=978-0-470-17023-6 |url=https://books.google.com/books?id=pUSG1BONmekC&pg=PA1577 |quote=Human sexual intercourse, or coitus, is one of the most common sexual outlets among adults. Sexual intercourse generally refers to penile penetration of the vagina.}}
* {{cite book| author = Clint E. Bruess| author2 = Elizabeth Schroeder|title = Sexuality Education Theory and Practice| publisher = ] | year = 2013 | page = 152 |isbn = 978-1-4496-4928-9| url =https://books.google.com/books?id=WWFW6-kkAVoC&pg=PA152|quote=In many cultures around the world, vaginal sex is what is usually implied when people refer to 'having sex' or 'sexual intercourse'. It is the most frequently studied behavior and is often the focus of sexuality education programming for youth.}}</ref> ''sex'' can be significantly broad in its meaning and may cover any penetrative or ] sexual activity between two or more people.<ref name="WHO, Sex"/> The ] (WHO) states that non-English languages and cultures use different words for sexual activity, "with slightly different meanings".<ref name="WHO, Sex"/> Various ], ], and ]s are used for sexual intercourse or other sexual activity, such as '']'', ''screw'', ''shag'', and the phrase "sleep together".<ref name="Fuck">{{cite dictionary|title=Fuck|dictionary=]|access-date=March 30, 2013|url=http://www.merriam-webster.com/dictionary/fuck}}</ref><ref>{{cite dictionary|title=Shag|dictionary=]|access-date=March 30, 2013|url=http://www.merriam-webster.com/dictionary/shag}}</ref><ref name="Sleep together">{{cite web|title=Sleep together|publisher=]|access-date=March 30, 2013|url=http://www.thefreedictionary.com/sleep+together}}</ref> The laws of some countries use the euphemism, ]. Penetration of the vagina by the ] penis is additionally known as ''intromission'', or by the Latin name ''] ]'' (Latin for "insertion of the penis").<ref name="Intromission">{{cite dictionary|title=Intromission| dictionary=]|access-date=December 26, 2012|url=http://www.merriam-webster.com/dictionary/intromission}}</ref> The age of first sexual intercourse is called ''sexarche''.<ref>{{cite web |title=sexarche - oi |publisher=Oxford University Press |work=Concise Medical Dictionary |url=http://oxfordindex.oup.com/view/10.1093/oi/authority.20110803100457655 |access-date=July 4, 2017 |archive-date=June 24, 2019 |archive-url=https://web.archive.org/web/20190624230226/https://oxfordindex.oup.com/view/10.1093/oi/authority.20110803100457655 |url-status=dead}}</ref><ref name="LaraAbdo2016">{{cite journal|vauthors=Lara LS, Abdo CH|title=Age at Time of Initial Sexual Intercourse and Health of Adolescent Girls|journal=Journal of Pediatric and Adolescent Gynecology|volume=29|issue=5|year=2016|pages=417–423|issn=1083-3188|doi=10.1016/j.jpag.2015.11.012|pmid=26655691}}</ref>


Vaginal, anal and oral sex are recognized as sexual intercourse more often than other sexual behaviors.<ref name="Most common forms">
== In humans ==
* {{cite web| title= Sexual Intercourse | publisher=]| access-date=January 12, 2008 | url=http://health.discovery.com/centers/sex/sexpedia/intercourse.html |archive-url =https://web.archive.org/web/20080822040701/http://health.discovery.com/centers/sex/sexpedia/intercourse.html|archive-date = August 22, 2008}}
{{See also|Human sexual behavior|Human sexuality}}
* {{cite book|author = Harvey B. Milkman|author2 = Kenneth W. Wanberg | title = Pathways to Self-Discovery and Change: Criminal Conduct and Substance Abuse Treatment for Adolescents | publisher = ] | year = 2004 | pages = 254–255|isbn = 978-1-4129-0614-2| url =https://books.google.com/books?id=2ovqg5jfsN0C&pg=PA254}}
{{Portalpar|Sexuality}}
* {{cite book| author = Nancy W. Denney| author2 = David Quadagno | title = Human Sexuality | publisher = ] | year = 2008 | page = 273|isbn = 978-0-8016-6374-1}}</ref> Sexual activity that does not involve penile-vaginal sex or other sexual penetration might be used to retain virginity (sometimes called ]) or labeled ''outercourse''.<ref name="Technical virginity">
'''Vaginal sexual intercourse''', also called '''coitus''', is the human form of copulation. While a purpose and effect is reproduction, it is often performed exclusively for pleasure and/or as an expression of love and emotional intimacy. Sexual intercourse typically plays a powerful ] role; in many societies it is normal for couples to have frequent intercourse while using ], sharing pleasure and strengthening their emotional bond through sex even though they are deliberately avoiding pregnancy.
* See and for views on what constitutes virginity loss and therefore sexual intercourse or other sexual activity; source discusses how gay and lesbian individuals define virginity loss, and how the majority of researchers and heterosexuals define virginity loss/"technical virginity" by whether a person has engaged in penile–vaginal sex. {{Cite book|author=Laura M. Carpenter|title=Virginity Lost: An Intimate Portrait of First Sexual Experiences|publisher=]|year = 2005|access-date=October 9, 2011|pages=295 pages |isbn=978-0-8147-1652-6|url=https://books.google.com/books?id=pXXZn_qSoDoC}}
* {{Cite book|author1=Bryan Strong |author2=Christine DeVault |author3=Theodore F. Cohen |author1-link=Bryan Strong |title=The Marriage and Family Experience: Intimate Relationship in a Changing Society| publisher = ]|year = 2010|page = 186| isbn = 978-0-534-62425-5|url=https://books.google.com/books?id=qjvoSOMB5JMC&pg=PA186|quote=Most people agree that we maintain virginity as long as we refrain from sexual (vaginal) intercourse. ...But occasionally we hear people speak of 'technical virginity' ... Other research, especially research looking into virginity loss, reports that 35% of virgins, defined as people who have never engaged in vaginal intercourse, have nonetheless engaged in one or more other forms of heterosexual activity (e.g. oral sex, anal sex, or mutual masturbation). ... Data indicate that 'a very significant proportion of teens ha had experience with oral sex, even if they haven't had sexual intercourse, and may think of themselves as virgins'.}}
* {{cite book | title = Our Sexuality | publisher = ] | year = 2010 | pages = 286–289 |isbn = 978-0-495-81294-4| url = https://books.google.com/books?id=MpRnPtmdRVwC&pg=PA286|quote=Noncoital forms of sexual intimacy, which have been called outercourse, can be a viable form of birth control. Outercourse includes all avenues of sexual intimacy other than penile–vaginal intercourse, including kissing, touching, mutual masturbation, and oral and anal sex. |author1=Robert Crooks |author2=Karla Baur }}
* {{cite book|vauthors=UD, TK|title =Promoting Healthy Behaviour: A Practical Guide | publisher = ] | year = 2014 | pages = 243–248|isbn =978-1-317-81887-8| url =https://books.google.com/books?id=63XMAgAAQBAJ&pg=PA243}}</ref> One reason virginity loss is often based on penile–vaginal intercourse is because heterosexual couples may engage in anal or oral sex as a way of being sexually active while maintaining that they are virgins since they have not engaged in the reproductive act of coitus.<ref name="Technical virginity 2">
* See and for views on what constitutes virginity loss and therefore sexual intercourse or other sexual activity; source discusses how gay and lesbian individuals define virginity loss, and how the majority of researchers and heterosexuals define virginity loss/"technical virginity" by whether a person has engaged in penile–vaginal sex. {{Cite book|author=Laura M. Carpenter|title=Virginity Lost: An Intimate Portrait of First Sexual Experiences|publisher=]|year = 2005|access-date=October 9, 2011|pages=295 pages |isbn=978-0-8147-1652-6|url=https://books.google.com/books?id=pXXZn_qSoDoC}}
* {{Cite book|author1=Bryan Strong |author2=Christine DeVault |author3=Theodore F. Cohen |author1-link=Bryan Strong |title=The Marriage and Family Experience: Intimate Relationship in a Changing Society| publisher = ]|year = 2010|page = 186| isbn = 978-0-534-62425-5|url=https://books.google.com/books?id=qjvoSOMB5JMC&pg=PA186|quote=Most people agree that we maintain virginity as long as we refrain from sexual (vaginal) intercourse. ...But occasionally we hear people speak of 'technical virginity' ... Other research, especially research looking into virginity loss, reports that 35% of virgins, defined as people who have never engaged in vaginal intercourse, have nonetheless engaged in one or more other forms of heterosexual activity (e.g. oral sex, anal sex, or mutual masturbation). ... Data indicate that 'a very significant proportion of teens ha had experience with oral sex, even if they haven't had sexual intercourse, and may think of themselves as virgins'.}}
* {{cite book|vauthors=UD, TK|title =Promoting Healthy Behaviour: A Practical Guide | publisher = ] | year = 2014 | pages = 243–248|isbn =978-1-317-81887-8| url = https://books.google.com/books?id=63XMAgAAQBAJ&pg=PA243}}</ref> Some ] consider ] or oral sex as a way of maintaining their virginities, with penile-anal penetration used as sexual intercourse and for virginity loss, while other gay men may consider frot or oral sex as their main forms of sexual activity.<ref name="Carpenter"/><ref name="Virgin">{{cite magazine|vauthors=Gross MJ|title = Like a Virgin|id = 0001-8996|magazine=]|publisher=]|year=2003|pages=44–45|access-date=March 13, 2011|url=https://books.google.com/books?id=eWQEAAAAMBAJ&pg=PA44}}</ref><ref name="Dolby">{{cite magazine|vauthors=Dolby T|title=Why Some Gay Men Don't Go All The Way|magazine=]|date=February 2004|access-date=February 12, 2011|pages=76–77|publisher=Here|url=https://books.google.com/books?id=jmIEAAAAMBAJ&pg=PA76}}</ref> Lesbians may categorize oral sex or ] as sexual intercourse and subsequently an act of virginity loss,<ref name="Carpenter">See and for views on what constitutes virginity loss and therefore sexual intercourse or other sexual activity; source discusses how gay and lesbian individuals define virginity loss, and how the majority of researchers and heterosexuals define virginity loss/"technical virginity" by whether a person has engaged in penile–vaginal sex. {{Cite book|vauthors=Carpenter LM|title=Virginity Lost: An Intimate Portrait of First Sexual Experiences|publisher=]|year = 2005|pages=295 pages |isbn=978-0-8147-1652-6|url=https://books.google.com/books?id=pXXZn_qSoDoC}}</ref><ref name="Lerner">{{cite book|vauthors=Lerner RM, Steinberg L|title = Handbook of Adolescent Psychology | publisher = ] | year = 2004 | pages = 193–196 |isbn = 978-0-471-69044-3| url = https://books.google.com/books?id=_wXasY1HyAYC&pg=PA193|quote=When researchers use the term ''sex'', they nearly always mean sexual intercourse&nbsp;– more specifically, penile–vaginal intercourse... The widespread, unquestioned equation of penile–vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question matches what the researcher had in mind.'}}</ref> or ] as a primary form of sexual activity.<ref name="Greenberg">{{cite book|vauthors=Greenberg JS, Bruess CE, Conklin SC|title= Exploring the Dimensions of Human Sexuality|id = 9780763741488|publisher=]|year=2007|page=429|url=https://books.google.com/books?id=ZdYh_iFZvbkC&pg=PA429|isbn =978-0-7637-4148-8}}</ref><ref name="Weiten3">{{cite book|vauthors=Weiten W, Dunn DS, Hammer EY|title=Psychology Applied to Modern Life: Adjustment in the 21st Century|id =1305968476|publisher=]|year=2016|page=349|isbn =978-0-7637-4148-8|access-date=December 27, 2017|url=https://books.google.com/books?id=09S5DQAAQBAJ&pg=PA349}}</ref>


Researchers commonly use ''sexual intercourse'' to denote penile–vaginal intercourse while using specific words, such as ''anal sex'' or ''oral sex'', for other sexual behaviors.<ref name="Researchers">
Sexual intercourse may also be defined as referring to other forms of insertive sexual behavior, such as ] and ]. The phrase '''to have sex''' can mean any or all of these behaviors, as well as other ] acts not considered here.
* {{cite book|title= Exploring Human Sexuality: Making Healthy Decisions|id = 9780763741488|publisher=]|year=2003|page=229|isbn =978-0-205-38059-6|author1=Richard D. McAnulty |author2=M. Michele Burnette }}
* {{cite book | title = Handbook of Adolescent Psychology | publisher = ] | year = 2004 | pages = 193–196 |isbn = 978-0-471-69044-3| url = https://books.google.com/books?id=_wXasY1HyAYC&pg=PA193|quote=When researchers use the term ''sex'', they nearly always mean sexual intercourse&nbsp;– more specifically, penile–vaginal intercourse... The widespread, unquestioned equation of penile–vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question matches what the researcher had in mind.'| author = Richard M. Lerner| author-link = Richard M. Lerner| author2 = Laurence Steinberg| author2-link = Laurence Steinberg}}
Coitus may be preceded by ], which leads to ] of the partners, resulting in the ] of the ] and natural ] of the ]. To engage in coitus, the erect penis is inserted into the vagina and one or both of the partners move their hips to move the penis backward and forward inside the vagina to cause ], typically without fully removing the penis. In this way, they stimulate themselves and each other, often continuing until ] in either or both partners is achieved. Penetration by the hardened erect penis is also known as '''intromission''', or by the Latin name ''] ]'' (Latin for "insertion of the penis").
* See and for views on what constitutes virginity loss and therefore sexual intercourse or other sexual activity; source discusses how gay and lesbian individuals define virginity loss, and how the majority of researchers and heterosexuals define virginity loss/"technical virginity" by whether a person has engaged in penile–vaginal sex. {{Cite book|author=Laura M. Carpenter|title=Virginity Lost: An Intimate Portrait of First Sexual Experiences|publisher=]|year = 2005|access-date=October 9, 2011|pages=295 pages |isbn=978-0-8147-1652-6|url=https://books.google.com/books?id=pXXZn_qSoDoC}}
* {{cite book | title = Handbook of Health Psychology | edition = 2nd|publisher = ] | year = 2012 | pages = 259–260 |isbn = 978-0-8058-6461-8| url =https://books.google.com/books?id=FZOjc8ouMlsC&pg=PA259|author1=Andrew Baum |author2=Tracey A. A. Revenson |author3=Jerome Singer }}
* {{cite book|vauthors=Aggleton P, Ball A, Mane P|title = Sex, Drugs and Young People: International Perspectives| publisher = ] | year = 2013 | page = 74|isbn =978-1-134-33310-3| url =https://books.google.com/books?id=HWcnAAAAQBAJ|quote=Having started with a discussion of penile-vaginal intercourse as the act that designates sexual initiation, as defined in most studies, we would like to undercut that position by stressing the need to define sex more broadly.}}</ref> Scholars ] and ] state that researchers also "rarely disclose" how they conceptualize sex "or even whether they resolved potential discrepancies" in conceptualizations of sex.<ref name="Lerner"/> Lerner and Steinberg attribute researchers' focus on penile–vaginal sex to "the larger culture's preoccupation with this form of sexual activity", and have expressed concern that the "widespread, unquestioned equation of penile–vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question matches what the researcher had in mind'".<ref name="Lerner"/> This focus can also relegate other forms of mutual sexual activity to ] or contribute to them not being regarded as "real sex", and limits the meaning of ].<ref name="Baum">{{cite book |vauthors=McClelland SI |veditors=Baum A, Revenson TA, Singer J |chapter=Measuring Sexual Quality of Life: Ten Recommendations for Health Psychologists |title=Handbook of Health Psychology |edition=2nd |publisher=] |year=2012 |pages=259–260 |access-date=April 30, 2013 |isbn=978-0-8058-6461-8 |chapter-url=https://books.google.com/books?id=FZOjc8ouMlsC&pg=PA259}}</ref><ref name="Kalbfleisch">{{cite book|vauthors= Kalbfleisch PJ, Cody MJ| title = Gender Power and Communication in Human Relationships | publisher = ] | year = 2012 | page = 153 | access-date = April 30, 2013|isbn = 978-1-136-48050-8| url = https://books.google.com/books?id=LyMo1RUJwj0C&pg=PA153}}</ref> It may also be that conceptually conflating sexual activity with vaginal intercourse and sexual function hinders and limits information about sexual behavior that ] people may be engaging in, or information about heterosexuals who may be engaging in non–vaginal sexual activity.<ref name="Baum"/>


Studies regarding the meaning of sexual intercourse sometimes come into conflict. While most consider penile–vaginal intercourse to be sex, whether anal or oral intercourse are considered sex is more debatable, with oral sex ranking lowest.<ref name="Upton">{{cite book|vauthors=UD, TK|title =Promoting Healthy Behaviour: A Practical Guide | publisher = ] | year = 2014 | pages = 243–248|isbn =978-1-317-81887-8| url =https://books.google.com/books?id=63XMAgAAQBAJ&pg=PA243}}</ref><ref name="Aggleton 1">{{cite book|vauthors=Aggleton P, Ball A, Mane P|title = Sex, Drugs and Young People: International Perspectives| publisher = ] | year = 2013 | pages = 74–75|isbn =978-1-134-33310-3| url =https://books.google.com/books?id=HWcnAAAAQBAJ}}</ref> The ] (CDC) stated that "although there are only limited national data about how often adolescents engage in oral sex, some data suggest that many adolescents who engage in oral sex do not consider it to be 'sex'; therefore they may use oral sex as an option to experience sex while still, in their minds, remaining abstinent".<ref name="CDC, oral sex">{{cite web|title=Oral Sex and HIV Risk |date=June 2009 |access-date=August 30, 2013 |publisher=] (CDC) |url=https://www.cdc.gov/hiv/resources/Factsheets/pdf/oralsex.pdf |url-status=dead |archive-url=https://web.archive.org/web/20130510210937/http://www.cdc.gov/hiv/resources/Factsheets/pdf/oralsex.pdf |archive-date=May 10, 2013 }}</ref> Upton et al. stated, "It is possible that individuals who engage in oral sex, but do not consider it as 'sex', may not associate the acts with the potential health risks they can bring."<ref name="Upton"/> In other cases, ] use is a factor, with some men stating that sexual activity involving the protection of a condom is not "real sex" or "the real thing".<ref name="Engel">{{cite book| author = Jonathan Engel | title = The Epidemic: A History of Aids | publisher = ] | year = 2009 | page = 242 | access-date = August 30, 2013 |isbn = 978-0-06-185676-1| url = https://books.google.com/books?id=GQud7Hf6oLIC&pg=PT242|quote=Many men simply did not like the feel of condoms, or associated them with emasculation. They say, 'Unless it's flesh on flesh, it's not real sex...}}</ref><ref name="Wekwete">{{cite book| author = Naomi N. Wekwete | title = Adolescent Pregnancy Challenges in the Era of HIV and AIDS: A Case Study of a Selected Rural Area in Zimbabwe | publisher = African Books Collective | year = 2010 | page = 49 | access-date = August 30, 2013 |isbn = 978-99944-55-48-5| url=https://books.google.com/books?id=LB45dcqSOpsC&pg=PA49}}</ref> This view is common among men in Africa,<ref name="Engel"/><ref name="Wekwete"/> where sexual activity involving the protection of a condom is often associated with ] because condoms prevent direct penile–to–skin genital contact.<ref name="Engel"/>
Coitus is the basic reproductive method of humans. During ejaculation, which usually accompanies male orgasm, a series of muscular ] delivers ] containing male ]s known as sperm cells or ] from the penis into the ].


===Stimulation===
The subsequent route of the sperm from the vault of the vagina is through the ] and into the ], and then into the ]s. Millions of sperm are present in each ejaculation, to increase the chances of one fertilizing an egg or ]. When a fertile ovum from the female is present in the fallopian tubes, the male gamete joins with the ovum, resulting in ] and the formation of a new ]. When a fertilized ovum reaches the uterus, it becomes implanted in the lining of the uterus, known as ], and a ] begins.
Sexual intercourse or other sexual activity can encompass various ] factors (] or ]), including different ]s (such as the ], the most common human sex position<ref name=":0">], Rodríguez, M., & González, M. I. (2017). . {{ill|Cuadernos de Investigación UNED|es}}, 9(1), 59-64.</ref>) or the use of ]s.<ref name="Weiten, 2008">{{cite book |title=Psychology Applied to Modern Life: Adjustment in the 21st Century |isbn = 978-0-495-55339-7 |publisher=] |year=2008 |pages=422–423 |access-date=January 5, 2012 |url=https://archive.org/details/isbn_2900495553396/page/422/ |author1=Wayne Weiten |author2=Margaret A. Lloyd |author3=Dana S. Dunn |author4=Elizabeth Yost Hammer |quote=The man-above, or "missionary," position is the most common ].}}</ref><ref name="Taormino">{{cite book |last=Taormino |first=Tristan |author-link=Tristan Taormino |title=The Big Book of Sex Toys|publisher=Quiver|year=2009 |access-date=June 9, 2014|page=52|isbn=978-1-59233-355-4|url=https://books.google.com/books?id=Hfly-iMkWRkC&pg=PA52}}</ref> ] may precede some sexual activities, often leading to ] of the partners and resulting in the erection of the ] or ] of the ].<ref name="Weiten, 2011">{{cite book|title=Psychology Applied to Modern Life: Adjustment in the 21st Century|isbn =978-1-111-18663-0|publisher=]|year=2011|pages=384–386|access-date=January 5, 2012|url=https://books.google.com/books?id=CGu96TeAZo0C&pg=PT421 |author1=Wayne Weiten |author2=Dana S. Dunn |author3=Elizabeth Yost Hammer }}</ref> It is also common for people to be as sexually satisfied by being kissed, touched ], or held as they are during sexual intercourse.<ref name="Alters2">{{cite book| author = Sandra Alters| author2 = Wendy Schiff|title =Essential Concepts for Healthy Living Update|publisher = ] | year = 2011 | page = | access-date = December 9, 2014 |isbn = 978-1-4496-5374-3| url =https://archive.org/details/essentialconcept00sand_1| url-access = registration}}</ref>


Non-] females copulate only when in ],<ref name="Pfaus2015"/> but sexual intercourse is possible at any time of the ] for women.<ref name="Reis"/><ref name="Dixson2012">Dixson A.F. (2012) Oxford University Press, 2nd edition.</ref> ] facilitate copulatory reflexes in various organisms, but, ], the detection of pheromones is impaired and they have only residual effects.<ref name="doty2014">Doty R.L. (2014) in Mucignat-Caretta C. (Ed). ''Neurobiology of Chemical Communication.'' Boca Raton (FL): CRC Press, (19).</ref> Non-primate females put themselves in the crucial ] and remain motionless, but these motor copulatory reflexes are no longer functional in women.<ref name="Pfaus2015">Pfaus J.G., Flanagan-Cato L.M., Blaustein J.D. (2015) Female sexual behavior. in Plant T., Zeleznik A. (Eds). Knobil and Neill's Physiology of Reproduction. Academic Press, 4th edition</ref>
Unlike most species, human sexual activity is not linked to periods of ] and can take place at any time during the reproductive cycle, even during pregnancy.<ref>{{cite book
|title=]
|year=1997
|last=Diamond
|first=Jared
|authorlink=Jared Diamond
}}</ref>
===Coitus difficulties===


] depiction of a ], a position that is more likely to stimulate the clitoris<ref name="Roberts">{{cite book|title=Sex|publisher=Lotus Press|year=2006|page=145|isbn = 978-81-89093-59-4|access-date=August 17, 2012|url=https://books.google.com/books?id=zDS9kC03x2IC&pg=PA145|author=Keath Roberts}}</ref>]]
] is regular difficulty reaching orgasm after ample sexual stimulation, causing personal distress. This is much more common in women than men. The physical structure of the act of coitus favors penile stimulation over clitoral stimulation. The location of the clitoris then often necessitates manual stimulation in order for the female to achieve ]. About 15 percent of women report difficulties with orgasm, and as many as 10 percent of women in the United States have never climaxed. Even women who orgasm regularly only climax about 50 percent to 70 percent of the time.<ref>Mayo Clinic; Womans Health </ref>
During coitus, the partners orient their hips to allow the penis to move back and forth in the vagina to cause friction, typically without fully removing the penis. In this way, they stimulate themselves and each other, often continuing until orgasm in either or both partners is achieved.<ref name="Kahn, Fawcett"/><ref name="Starr2">{{cite book|title=Human Biology|isbn =978-0-495-56181-1|publisher=]|year=2008|page=314|access-date=April 30, 2013|url=https://books.google.com/books?id=09reWGhFDqUC&pg=PA314|author1=Cecie Starr |author2=Beverly McMillan }}</ref>


For human females, stimulation of the ] plays a significant role in sexual activity; 70–80% of women require direct clitoral stimulation to achieve orgasm,<ref name="Flaherty">{{cite book|title=Psychiatry: Diagnosis & therapy. A Lange clinical manual|isbn=978-0-8385-1267-8|publisher=] (Original from Northwestern University)|year=1993|pages=|url=https://archive.org/details/psychiatrydiagno00flah/page/544|quote=The amount of time of sexual arousal needed to reach orgasm is variable&nbsp;— and usually much longer&nbsp;— in women than in men; thus, only 20–30% of women attain a coital climax. b. Many women (70–80%) require manual clitoral stimulation...|author1=Joseph A. Flaherty|author2=John Marcell Davis|author3=Philip G. Janicak}}</ref><ref name="Kenneth Mah">{{cite journal |vauthors=Mah K, Binik YM | title = The nature of human orgasm: a critical review of major trends | journal = ] | volume = 21 | issue = 6 | pages = 823–856 |date=January 7, 2001 | pmid = 11497209 | doi = 10.1016/S0272-7358(00)00069-6 | quote = Women rated clitoral stimulation as at least somewhat more important than vaginal stimulation in achieving orgasm; only about 20% indicated that they did not require additional clitoral stimulation during intercourse.}}</ref><ref name="Kammerer-Doak">{{cite journal |vauthors=Kammerer-Doak D, Rogers RG | title = Female Sexual Function and Dysfunction | journal = Obstetrics and Gynecology Clinics of North America | volume = 35 | issue = 2 | pages = 169–183 |date=June 2008 | pmid = 18486835 | doi = 10.1016/j.ogc.2008.03.006 | quote = Most women report the inability to achieve orgasm with vaginal intercourse and require direct clitoral stimulation ... About 20% have coital climaxes...}}</ref> though indirect clitoral stimulation (for example, via vaginal intercourse) may also be sufficient (see ]).<ref name="Lloyd">{{cite book |first=Elisabeth Anne|last=Lloyd|title=The case of the female orgasm: bias in the science of evolution|isbn = 978-0-674-01706-1|publisher=Harvard University Press|year=2005|page=53|access-date=January 5, 2012 |url=https://books.google.com/books?id=6GFNvA6TvlwC&pg=PA53|oclc=432675780}}</ref><ref name="O'Connell">{{cite journal |vauthors=O'Connell HE, Sanjeevan KV, Hutson JM | s2cid = 26109805 | title = Anatomy of the clitoris | journal = The Journal of Urology | volume = 174 | issue = 4 Pt 1 | pages = 1189–95 | date = October 2005 | pmid = 16145367 | doi = 10.1097/01.ju.0000173639.38898.cd }}<br />{{cite web |last=Mascall |first=Sharon |title=Time for rethink on the clitoris | url = http://news.bbc.co.uk/2/hi/health/5013866.stm | date =June 11, 2006 | work = ] }}</ref> Because of this, some couples may engage in the ] or the ], a technique combining the "riding high" variation of the missionary position with pressure-counterpressure movements performed by each partner in rhythm with sexual penetration, to maximize clitoral stimulation.<ref name="Roberts"/><ref name="Hurlbert">{{cite journal |vauthors=Hurlbert DF, Apt C | title = The coital alignment technique and directed masturbation: a comparative study on female orgasm | journal = ] | volume = 21 | issue = 1 | pages = 21–29 | year = 1995 | pmid = 7608994 | doi = 10.1080/00926239508405968 }}</ref>
Some males suffer from ] (ED), or ], at least occasionally. For those whose impotence is caused by medical conditions, prescription drugs such as ], ], and ] are available. However, doctors caution against the unnecessary use of these drugs because they are accompanied by serious risks such as increased chance of heart attack. Moreover, using a drug to counteract the symptom—impotence—can mask the underlying problem causing the impotence and does not resolve it. A serious medical condition might be aggravated if left untreated.
] depiction of ] in the life of ]]]
Anal sex involves stimulation of the ], anal cavity, sphincter valve or ]; it most commonly means the insertion of a man's penis into another person's rectum, but may also mean the use of sex toys or fingers to penetrate the anus, or oral sex on the anus (]), or ].<ref name="Answer">{{cite book|author1-link=Barry Komisaruk|author1=Barry R. Komisaruk|author2=Beverly Whipple|author2-link=Beverly Whipple|author3=Sara Nasserzadeh|author3-link=Sara Nasserzadeh|author4 =Carlos Beyer-Flores|title=The Orgasm Answer Guide|isbn = 978-0-8018-9396-4|publisher=]|year=2009|pages=–109|access-date=November 6, 2011|url=https://archive.org/details/orgasmanswerguid00komi|url-access =registration}}</ref>


Oral sex consists of all the sexual activities that involve the use of the mouth and throat to stimulate ] or anus. It is sometimes performed to the exclusion of all other forms of sexual activity, and may include the ingestion or absorption of semen (during ]) or vaginal fluids (during ]).<ref name="Weiten, 2008"/><ref name="Kamen">{{Cite book| author = Paula Kamen| title = Her Way: Young Women Remake the Sexual Revolution | isbn = 978-0-8147-4733-9| publisher = ]| year = 2000|pages = 74–77| access-date=September 5, 2012|url=https://books.google.com/books?id=9bXq3Qc4py0C&pg=PA74}}</ref>
A more common sexual disorder in males is ] (PE). The U.S. ] is examining the drug ] to treat premature ejaculation. In clinical trials, those with PE who took dapoxetine experienced intercourse three to four times longer before orgasm than without the drug. Another ejaculation-related disorder is ], which can be caused as an unwanted side effect of antidepressant medications such as ].<ref>{{cite journal| last = Riley| first = A.
| authorlink = | coauthors = R.T. Segraves| title = Treatment of Premature Ejaculation| journal = Int J. Clin Pract.| volume = 60| issue = 6| pages = 694–697| publisher = Blackwell Publishing| location = | year = 2006| url = http://www.medscape.com/viewarticle/533889_print| doi = 10.1111/j.1368-5031.2006.00818.x| id = | accessdate = 2008-02-01| pmid = 16805755| last1 = Riley| first1 = A| last2 = Segraves| first2 = RT}}</ref><ref>{{cite journal | first = Waldinger MD | last = Hengeveld VW et al. | year = 1998 | title = Effect of SSRI antidepressants on ejaculation: a double blind, randomised, placebo-controlled study with fluoxetine, fluvoxamine, paroxetine and sertraline | journal = Journal of Clinical Psychopharmacology | volume = 18 | issue = | pages = 274–281 | doi = 10.1097/00004714-199808000-00004}}</ref>


Fingering involves the digital manipulation of the clitoris, rest of the ], vagina or anus for the purpose of sexual arousal and sexual stimulation; it may constitute the entire sexual encounter or it may be part of mutual masturbation, foreplay or other sexual activities.<ref name="Kinetics"/><ref name="Hite">{{cite book|last=Hite|first=Shere|author-link=Shere Hite|title=The Hite Report: A Nationwide Study of Female Sexuality |publisher=]|year=2003|location=New York, NY|pages=512 pages|isbn=978-1-58322-569-1|access-date=March 2, 2012|url=https://books.google.com/books?id=s3OZaVn2wfkC&pg=PP1}}</ref><ref name="Carroll2">{{cite book | title =Sexuality Now: Embracing Diversity | publisher = ] | year = 2009 | pages = 118, 252, and 264 | access-date =June 23, 2012 | url = https://books.google.com/books?id=5f8mQx7ULs4C&pg=PA118|isbn =978-0-495-60274-3| first = Janell L. | last = Carroll}}
The American Urological Association (AUA) estimates that premature ejaculation could affect 27 to 34 percent of men in the United States. The AUA also estimates that 10 to 12 percent of men in the United States are affected by erectile dysfunction. ] is involuntary tensing of the pelvic floor musculature, making coitus distressing, painful, and sometimes impossible.<ref name= Reissing> Reissing ED, Binik YM, Khalifé S, Cohen D, Amsel R. ( 2003) ''Etiological correlates of vaginismus: sexual and physical abuse, sexual knowledge, sexual self-schema, and relationship adjustment''. J Sex Marital Ther.29:47-59.</ref><ref name= Ward> Ward E, Ogden J. (1994) ''Experiencing Vaginismus: sufferers beliefs about causes and effects''. The Journal of Nervous and Mental Disease 9 (1): 33–45. </ref> ] is a medical term signifying painful or uncomfortable intercourse, but does not specify the cause.<ref name=binik2005>{{cite journal |author=Binik YM |title=Should dyspareunia be retained as a sexual dysfunction in DSM-V? A painful classification decision |journal=Arch Sex Behav |volume=34 |issue=1 |pages=11–21 |year=2005 |month=Feb |pmid=15772767 |doi=10.1007/s10508-005-0998-4 }}</ref><ref name=Peckham86>{{cite journal |author=Peckham BM, Maki DG, Patterson JJ, Hafez GR |title=Focal vulvitis: a characteristic syndrome and cause of dyspareunia. Features, natural history, and management |journal=Am J Obstet Gynecol. |volume=154 |issue=4 |pages=855–64 |year=1986 |month=Apr |pmid=3963075 }}</ref>
</ref>


===Reproduction===
Although ]-related pain and mobility impairment can hamper intercourse, in many cases the most significant impediments to intercourse for individuals with a disability are psychological.<ref name="Williamson">{{cite journal
{{Main|Sexual reproduction|Human reproduction}}
| last = Williamson
] by ] day relative to ovulation<ref name="DunsonBaird1999">{{cite journal|last1=Dunson|first1=D.B.|author1-link=David Dunson|last2=Baird|first2=D.D.|author2-link=Donna Baird|last3=Wilcox|first3=A.J.|last4=Weinberg|first4=C.R.|author4-link=Clarice Weinberg|title=Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation|journal=Human Reproduction|volume=14|issue=7|year=1999|pages=1835–1839|issn=1460-2350|doi=10.1093/humrep/14.7.1835|pmid=10402400|doi-access=free}}</ref>]]
| first = Gail M.
]]]
| coauthors = Walters, Andrew S.
Natural human reproduction involves penile–vaginal penetration,<ref name="Evan Jones">{{cite book |title=Human Reproductive Biology |isbn =978-0-12-088465-0 |publisher=] |year=2006 |pages= |access-date=June 5, 2022 <!-- Coitus (sexual intercourse) --> |url=https://archive.org/details/humanreproductiv0000jone_l0u3|url-access=registration|author1=Richard Evan Jones |author2=Kristin H. López }}</ref> during which ], containing male gametes known as ] cells or spermatozoa, is ] through the penis into the vagina. The sperm passes through the ], ] and into the ], and then into the ]s. Millions of sperm are ejaculated to increase the chances of ] (see ]), but only one is sufficient to fertilize an egg or ]. When a fertile ovum from the female is present in the fallopian tubes, the male gamete fertilizes the ovum, forming a new ]. ] begins after the fertilized ovum is implanted in the lining of the uterus (the ]).<ref name="Evan Jones"/><ref name="Starr3">{{cite book| author = Cecie Starr|author2= Beverly McMillan|title = Human Biology| publisher = ] | year = 2015 | page = 339| access-date = December 27, 2017 |isbn = 978-1-305-44594-9| url =https://books.google.com/books?id=lS5-BAAAQBAJ&pg=PT339}}</ref>
| year = 1996
| title = Perceived Impact of Limb Amputation on Sexual Activity: A Study of Adult Amputees
| journal = The Journal of Sex Research
| volume = 33
| issue = 3
| pages = 221–230
| publisher = Lawrence Erlbaum Associates (Taylor & Francis Group)
| issn = 00224499
| oclc =39109327
| url = http://www.jstor.org/stable/3813582
| doi = 10.2307/3813582
| doi_brokendate = 2009-06-05
| day = 01
}}</ref> In particular, people who have a disability can find intercourse daunting due to issues involving their ] as a sexual being,<ref name="Majiet">{{Cite journal
| last = Majiet
| first = Shanaaz
| title = Disabled Women and Sexuality
| journal = Agenda
| issue = 19
| publisher = Agenda Feminist Media
| pages = 43–44
| year = 1993
| url = http://www.jstor.org/stable/4065995
| doi = 10.2307/4065995
| day = 01
}}</ref><ref name="Dewolfe">{{cite journal
| last = Dewolfe
| first = Deborah J.
| coauthors = Livingston, Carolyn A.
| year = 1982
| month = Aug.
| title = Sexual Therapy for a Woman with Cerebral Palsy: A Case Analysis
| journal = The Journal of Sex Research
| volume = 18
| issue = 3
| pages = 253–263
| publisher = Lawrence Erlbaum Associates (Taylor & Francis Group)
| issn = 00224499
| oclc = 39109327
| url = http://www.jstor.org/stable/3812217
| doi = 10.2307/3812217
| doi_brokendate = 2009-06-05
| day = 01
}}</ref> or partner's discomfort or perceived discomfort.<ref name="Williamson" />


] are highest during the ] time from some five days before until approximately one day after ovulation (this is sometimes called the ]).<ref name=":1">{{Cite journal |last1=Gibbons |first1=Tatjana |last2=Reavey |first2=Jane |last3=Georgiou |first3=Ektoras X |last4=Becker |first4=Christian M |date=September 15, 2023 |editor-last=Cochrane Gynaecology and Fertility Group |title=Timed intercourse for couples trying to conceive |journal=Cochrane Database of Systematic Reviews |language=en |volume=2023 |issue=9 |pages=CD011345 |doi=10.1002/14651858.CD011345.pub3|pmid=37709293 |pmc=10501857 }}</ref> For optimal pregnancy chance, there are recommendations of ] every one or two days,<ref>{{cite web|url=https://www.mayoclinic.org/healthy-lifestyle/getting-pregnant/in-depth/how-to-get-pregnant/art-20047611|title=How to get pregnant|website=]|date=November 2, 2016|access-date=February 16, 2018}}</ref> or every two or three days.<ref>{{cite web|url=https://www.nice.org.uk/guidance/cg156/ifp/chapter/trying-for-a-baby|title=Fertility problems: assessment and treatment, Clinical guideline |website=]|date=February 20, 2013 |access-date=February 16, 2018}} Published date: February 2013. Last updated: September 2017</ref> Some people who are trying to conceive may choose to time vaginal intercourse with the fertile window, a practice that is sometimes called 'timed intercourse'.<ref name=":1" /> Timed intercourse using urine tests that predict ovulation may help improve the rate of pregnancy and live births for some couples trying to conceive such as those who have been trying for less than 12 months and who are under 40 years old; however, it is not clear from medical evidence if timed intercourse improves the rate of ultrasound-confirmed pregnancies and it is also not clear if timed intercourse has an effect on a person's level of stress or their quality of life.<ref name=":1" /> Studies have shown no significant difference between different ] and pregnancy rate, as long as it results in ] into the vagina.<ref name=americanpregnancy>{{cite web|url=http://americanpregnancy.org/getting-pregnant-ebook/p7M7O0q1c71703C/gettingpregnant.pdf|title=The Essential Guide to Getting Pregnant|website=American Pregnancy Association|author=Philip B. Imler & David Wilbanks|date=November 2019|access-date=February 16, 2018|archive-date=June 1, 2018|archive-url=https://web.archive.org/web/20180601033115/http://americanpregnancy.org/getting-pregnant-ebook/p7M7O0q1c71703C/gettingpregnant.pdf|url-status=dead}}</ref>
Temporary difficulties can arise with ] as alcohol initially increases interest (through disinhibition) but decreases capacity with greater intake.


When a ] has sexual intercourse with a woman who is not his partner and for the sole purpose of impregnating the woman, this may be known as natural ], as opposed to ]. Artificial insemination is a form of ], which are methods used to achieve pregnancy by artificial or partially artificial means.<ref name="Bobick and Balaban">{{cite book|author1=James Bobick |author2=Naomi Balaban |title=The Handy Anatomy Answer Book|isbn=978-1-57859-328-6|publisher=]|year=2008|pages=306–307|access-date=August 21, 2013|url=https://books.google.com/books?id=LBI2Sg2yYMoC&pg=PA305}}</ref> For artificial insemination, ] may donate their sperm through a ], and the insemination is performed with the express intention of attempting to impregnate the female; to this extent, its purpose is the medical equivalent of sexual intercourse.<ref name="Sharma">{{cite book|author=R.K. Sharma|title=Concise Textbook Of Forensic Medicine & Toxicology|isbn=978-81-312-1145-8|publisher=]|year=2007|pages=113–116|access-date=October 13, 2013|url=https://books.google.com/books?id=_zAwlKX_zNwC&pg=PA113}}</ref><ref name="O'Toole">{{cite book|author=Mosby, Marie T. O'Toole|title=Mosby's Medical Dictionary|isbn=978-0-323-11258-1|publisher=]|year=2013|page=138|access-date=October 13, 2013|url=https://books.google.com/books?id=aW0zkZl0JgQC&pg=PA138}}</ref> ], which involves the deposit of (usually) raw semen in the vagina of a woman, is in effect a substitute for intercourse and is often contrasted with 'normal intercourse' in this context. Reproductive methods also extend to gay and lesbian couples. For gay male pairings, there is the option of ] pregnancy; for lesbian couples, there is donor insemination in addition to choosing surrogate pregnancy.<ref name="Berkowitz">{{cite journal |vauthors=Berkowitz D, Marsiglio W | s2cid = 38458107 | year = 2007 | title = Gay Men: Negotiating Procreative, Father, and Family Identities | journal = Journal of Marriage and Family | volume = 69 | issue = 2| pages = 366–381 | doi = 10.1111/j.1741-3737.2007.00371.x }}</ref><ref name="Burda">{{Cite book| author = Joan M. Burda| title = Gay, lesbian, and transgender clients: a lawyer's guide | publisher = ]| year = 2008 |pages =69–74| isbn = 978-1-59031-944-4|access-date=July 28, 2011|url=https://books.google.com/books?id=QdzB1f8Y8Q8C&pg=PA69}}</ref> Some women use artificial insemination to become ].<ref>{{cite journal |last1=Fiese |first1=Barbara |title=Single Mothers by Choice: Mother–Child Relationships and Children's Psychological Adjustment |journal=J Fam Psychol |date=2016 |volume=30 |issue=4 |pages=409–418 |doi=10.1037/fam0000188 |pmid=26866836 |pmc=4886836 }}</ref>
==Functions of sex beyond reproduction==
===Health benefits===
Sex has been claimed to produce health benefits as varied as improved sense of smell,<ref>Farnham, A. (2003) ''Forbes''</ref> ], ] reduction, increased ], and decreased risk of ].<ref name="webmd.com">Doheny, K. (2008) ] (reviewed by Chang, L., M.D.)</ref>


===Safe sex and birth control===
Sex between cohabiting partners lowers ] and reduces stress, according to Stuart Brody, professor of psychology at the University of the West of Scotland. Brody's team monitored 24 women and 22 men who were exposed to stressful situations, such as speaking in public and doing verbal arithmetic, and kept records of their sexual activity. The men and women who had penile-vaginal intercourse responded more positively to stress "than those who engaged in other sexual behaviors or abstained".<ref name=webmd.com/><ref>Brody, S. ''Biological Psychology'', February 2006; vol 71: pp 214-222. Brody, S. ''Biological Psychology'', March 2000; vol 52: pp 251-257.</ref> A study by Keith Light of the University of North Carolina went as far as to find a link between "partner hug" and lower blood pressure in women.<ref name=webmd.com/><ref>Light, K.C. et al., "More frequent partner hugs and higher oxytocin levels are linked to lower blood pressure and heart rate in premenopausal women." ''Biological Psychology'', April 2005; vol 69: pp 5-21.</ref>
{{See also|Comparison of birth control methods}}
There are a variety of ] methods that are practiced by heterosexual and same-sex couples, including non-penetrative sex acts,<ref name="Kumar"/><ref name="Durham">{{cite book|title=The Person With HIV/AIDS: Nursing Perspectives|edition=3rd|isbn = 978-81-223-0004-8|publisher=]|year=2000|page=103|access-date=January 29, 2012|url=https://books.google.com/books?id=WSCQ4L8kSXsC&pg=PA103|author1=Jerry D. Durham |author2=Felissa R. Lashley }}</ref> and heterosexual couples may use oral or anal sex (or both) as a means of birth control.<ref name="Crooks">{{cite book | title = Our Sexuality | publisher = ] | year = 2010 | pages = 286–289 | access-date = August 30, 2012 |isbn = 978-0-495-81294-4| url = https://books.google.com/books?id=MpRnPtmdRVwC&pg=PA286|quote=Noncoital forms of sexual intimacy, which have been called outercourse, can be a viable form of birth control. Outercourse includes all avenues of sexual intimacy other than penile–vaginal intercourse, including kissing, touching, mutual masturbation, and oral and anal sex. |author1=Robert Crooks |author2=Karla Baur }}</ref><ref>{{cite journal |vauthors=Feldmann J, Middleman AB | title = Adolescent sexuality and sexual behavior | journal = Current Opinion in Obstetrics and Gynecology | volume = 14 | issue = 5 | pages = 489–493 | year = 2002 | pmid = 12401976 | doi=10.1097/00001703-200210000-00008| s2cid = 29206790 }}</ref> However, pregnancy can still occur with anal sex or other forms of sexual activity if the penis is near the vagina (such as during ] or other ]) and its sperm is deposited near the vagina's entrance and travels along the vagina's lubricating fluids; the risk of pregnancy can also occur without the penis being near the vagina because sperm may be transported to the vaginal opening by the vagina coming in contact with fingers or other non-genital body parts that have come in contact with semen.<ref>{{cite book|last=Thomas|first=R. Murray|title=Sex and the American teenager seeing through the myths and confronting the issues|year=2009|publisher=]|location=Lanham, Md.|isbn=978-1-60709-018-2|page=81|url=https://books.google.com/books?id=gM9EFgsJHyoC&pg=PA81|access-date=October 21, 2015}}</ref><ref>{{cite book|last=Edlin|first=Gordon|title=Health & Wellness.|year=2012|publisher=]|isbn=978-1-4496-3647-0|page=213|url=https://books.google.com/books?id=csGk6j5rlN0C&pg=PA213|access-date=October 21, 2015}}</ref>


Safe sex is a relevant ] philosophy<ref name="Mercer">{{cite journal | vauthors = Chin HB, Sipe TA, Elder R, Mercer SL, Chattopadhyay SK, Jacob V, Wethington HR, Kirby D, Elliston DB, Griffith M, Chuke SO, Briss SC, Ericksen I, Galbraith JS, Herbst JH, Johnson RL, Kraft JM, Noar SM, Romero LM, Santelli J | title = The Effectiveness of Group-Based Comprehensive Risk-Reduction and Abstinence Education Interventions to Prevent or Reduce the Risk of Adolescent Pregnancy, Human Immunodeficiency Virus, and Sexually Transmitted Infections | journal = American Journal of Preventive Medicine | volume = 42 | issue = 3 | pages = 272–294 | year = 2012 | pmid = 22341164 | doi = 10.1016/j.amepre.2011.11.006 | url = http://www.ajpmonline.org/article/S0749-3797(11)00906-8/abstract | access-date = July 23, 2013 | archive-date = January 2, 2020 | archive-url = https://web.archive.org/web/20200102180246/https://www.ajpmonline.org/article/S0749-3797(11)00906-8/abstract | url-status = dead }}</ref> and ]s are used as a form of safe sex and contraception. Condoms are widely recommended for the prevention of ] (STIs).<ref name="Mercer"/> According to reports by the ] (NIH) and ] (WHO), correct and consistent use of latex condoms reduces the risk of ] transmission by approximately 85–99% relative to risk when unprotected.<ref>{{cite conference|author=National Institute of Allergy and Infectious Diseases |author-link=National Institute of Allergy and Infectious Diseases |author2=National Institutes of Health, Department of Health and Human Services |title=Workshop Summary: Scientific Evidence on Condom Effectiveness for Sexually Transmitted Disease (STD) Prevention |pages=13–15 |date=July 20, 2001 |location=Hyatt Dulles Airport, Herndon, Virginia |url=http://www3.niaid.nih.gov/about/organization/dmid/PDF/condomReport.pdf |archive-url=https://web.archive.org/web/20100307132024/http://www3.niaid.nih.gov/about/organization/dmid/PDF/condomReport.pdf |archive-date=March 7, 2010 |access-date=March 20, 2009 |url-status=dead}}</ref><ref name="WHO condoms">{{cite web|title=Effectiveness of male latex condoms in protecting against pregnancy and sexually transmitted infections|publisher=]|year=2000|access-date=July 23, 2013|url=https://www.who.int/mediacentre/factsheets/fs243/en/index.html|archive-url=https://web.archive.org/web/20100509064325/http://www.who.int/mediacentre/factsheets/fs243/en/index.html |archive-date=May 9, 2010 }}</ref> Condoms are rarely used for oral sex and there is significantly less research on behaviors with regard to condom use for anal and oral sex.<ref name="Kumar 2">{{cite book|title=Sexually Transmitted Infections E book| author = Bhushan Kumar, Somesh Gupta| publisher = ] | year = 2014 | page = 122 |isbn = 978-81-312-2978-1| url =https://books.google.com/books?id=kQ9tAwAAQBAJ}}</ref> The most effective way to avoid sexually transmitted infections is to ] from sexual intercourse, especially vaginal, anal, and oral sexual intercourse.<ref name="Mercer"/>
Frequent sexual intercourse was held to reduce the risk of the common cold by Carl Charnetski and Francis X. Brennan of ] in Wilkes-Barre, Pa. These scientists linked frequent sexual intercourse (once or twice a week) to increased production of the ] called ] or IgA, which can protect the body from getting colds and other infections. They took samples of ], which contain IgA, from 112 college students who reported the frequency of sex they had. The students in the "frequent" group had higher levels of IgA than those in the other three groups, consisting of people who were ], had sex less than once a week, or had it "very often" (three or more times weekly). The other three groups had comparable IgA levels.<ref name=webmd.com/><ref>Charnetski CJ, Brennan FX. Sexual frequency and salivary immunoglobulin A (IgA). ''Psychological Reports'' 2004 Jun;94(3 Pt 1):839-44. Data on length of relationship and sexual satisfaction were not related to the group differences.</ref> Charnetski and Brennan had previously shown that exposure to elevator music has a similar effect on IgA levels.<ref>Charnetski CJ, Brennan FX Jr, Harrison JF. "Effect of music and auditory stimuli on secretory immunoglobulin A (IgA)." ''Perception and Motor Skills'' 1998 Dec;87(3 Pt 2):1163-70.</ref>


Decisions and options concerning birth control can be affected by cultural reasons, such as religion, ]s or ].<ref name="Hales2">{{cite book | title = An Invitation to Health: Choosing to Change| publisher = ]| year = 2010 | pages = 301–302| access-date = March 30, 2013 |isbn = 978-0-538-73655-8| url = https://books.google.com/books?id=yPa0LZXizO4C&pg=PA301 | author = Dianne Hales}}</ref> In the predominantly ] countries Ireland, Italy, and the Philippines, ] and the ] are emphasized while disapproval is expressed with regard to other contraceptive methods.<ref name="Hales"/> Worldwide, ] is a more common birth control method,<ref name="Hales"/> and use of the ] (IUD) is the most common and effective way of reversible contraception.<ref name="Hales"/><ref name=Winner2012>{{cite journal |vauthors=Winner B, Peipert JF, Zhao Q, Buckel C, Madden T, Allsworth JE, Secura GM | title = Effectiveness of long-acting reversible contraception | journal = N. Engl. J. Med. | volume = 366 | issue = 21 | pages = 1998–2007 | year = 2012 | pmid = 22621627 | doi = 10.1056/NEJMoa1110855 | s2cid = 16812353 | url = https://digitalcommons.wustl.edu/cgi/viewcontent.cgi?article=3776&context=open_access_pubs | doi-access = free }}</ref> Conception and contraception are additionally a life-and-death situation in ], where one in three women give birth before age 20; however, 90% of ]s in these countries could be prevented by effective contraception use.<ref name="Hales"/>
"Sex is a great mode of exercise," according to Patti Britton, ], past president of the American Association of Sexuality Educators, Counselors and Therapists (AASECT) and currently host of the website "Your Sex Coach". She notes that thirty minutes of sex burns 85 calories or more. She concludes that 42 half-hour sessions, or 21 hour-long sessions, will burn 3,570 calories - sufficient to lose one pound.<ref name=webmd.com/>


The ] (NSSHB) indicated in 2010 that "1 of 4 acts of vaginal intercourse are condom-protected in the U.S. (1 in 3 among singles)," that "condom use is higher among black and Hispanic Americans than among white Americans and those from other racial groups," and that "adults using a condom for intercourse were just as likely to rate the sexual extent positively in terms of arousal, pleasure and orgasm than when having intercourse without one".<ref name="NSSHB">{{cite journal |title=Findings from the National Survey of Sexual Health and Behavior, Centre for Sexual Health Promotion, Indiana University |journal= ] |volume=7 |issue=Supplement 5 |page=4 |year=2010 |access-date=March 4, 2011|url=http://www.kinseyinstitute.org/resources/FAQ.html}}</ref>
"Boosting self-esteem" was one of 237 reasons people have sex, collected by ] researchers and published in the journal ''Archives of Sexual Behavior.'' Some subjects who already had high self-esteem said they sometimes have sex to "feel even better".<ref name=webmd.com/>


===Prevalence===
Sexual intimacy, as well as orgasms, increases levels of the hormone ], also known as "the love hormone" which helps people bond and build trust. Researchers from the ] and the ] evaluated 59 premenopausal women before and after warm contact with their husbands and partners ending with hugs. They found that the more contact, the higher the oxytocin levels. Oxytocin allows people to feel the urge to nurture and to bond. ] has also been credited and linked to a higher level of oxytocin. In addition, as the hormone oxytocin surges, endorphins increase, and pain declines. In a study published in the ''Bulletin of Experimental Biology and Medicine'', 48 volunteers who inhaled oxytocin vapor and then had their fingers pricked lowered their pain threshold by more than half. The oxytocin released during orgasm also promotes sleep.<ref name=webmd.com/>
Penile–vaginal penetration is the most common form of sexual intercourse.<ref name="Alters"/><ref name="Carroll"/> Studies indicate that most heterosexual couples engage in vaginal intercourse nearly every sexual encounter.<ref name="Carroll"/> The National Survey of Sexual Health and Behavior (NSSHB) reported in 2010 that vaginal intercourse is "the most prevalent sexual behavior among men and women of all ages and ethnicities".<ref name="Carroll"/> Clint E. Bruess et al. stated that it "is the most frequently studied behavior" and is "often the focus of sexuality education programming for youth."<ref name="Bruess">{{cite book| author = Clint E. Bruess| author2 = Elizabeth Schroeder|title = Sexuality Education Theory and Practice| publisher = ] | year = 2013 | page = 152 | access-date = December 5, 2014 |isbn = 978-1-4496-4928-9| url =https://books.google.com/books?id=WWFW6-kkAVoC&pg=PA152}}</ref> Weiten et al. said that it "is the most widely endorsed and practiced sexual act in our society."<ref name="Weiten3"/>


Regarding oral or anal intercourse, the CDC stated in 2009, "Studies indicate that oral sex is commonly practiced by sexually active male-female and same-gender couples of various ages, including adolescents."<ref name="CDC, oral sex"/> Oral sex is significantly more common than anal sex.<ref name="Weiten3"/><ref name="Aggleton 1"/> The 2010 NSSHB study reported that vaginal intercourse was practiced more than insertive anal intercourse among men, but that 13% to 15% of men aged 25 to 49 practiced insertive anal intercourse. Receptive anal intercourse was infrequent among men, with approximately 7% of men aged 14 to 94 years old having said that they were a receptive partner during anal intercourse. The study said that fewer women reported engaging in anal sex than other partnered sexual behaviors. It was estimated that 10% to 14% of women aged 18 to 39 years old practiced anal sex in the past 90 days, and that most of the women who engage in anal sex said they practiced it once a month or a few times a year.<ref name="Carroll"/>
Men who have frequent ejaculations, especially men in their 20s, may reduce their risks of prostate cancer later in life. ]n researchers reported in the ''British Journal of Urology International'' that they followed men diagnosed with prostate cancer and those without. They found no association of prostate cancer with the number of sexual partners as the men reached their 30s, 40s, and 50s, but men who had five or more ejaculations weekly while in their 20s reduced their risk of getting prostate cancer later by a third. Another study, reported in the ], "found that frequent ejaculations, 21 or more a month, were linked to lower prostate cancer risk in older men, as well, compared with less frequent ejaculations of four to seven monthly".<ref name=webmd.com/>


===={{anchor|sexarche}}Age at first intercourse====
During sex, pelvic floor muscle exercises known as ] offer benefits for women. More sexual pleasure is expected to result, strengthening of the area, and help to minimize the risk of incontinence later in life.<ref name=webmd.com/>
The prevalence of sexual intercourse has been compared cross-culturally. In 2003, Michael Bozon of the French ] conducted a cross-cultural study titled "At what age do women and men have their first sexual intercourse?" In the first group of the contemporary cultures he studied, which included ] (listing ], ] and ]), the data indicated that the age of men at sexual initiation in these societies is at later ages than that of women, but is often extra-marital; the study considered the ] to also fall into this group, though data was only available from ].<ref name="Bozon">{{cite journal |last=Bozon |first=Michael |year=2003 |title=At what age do women and men have their first sexual intercourse? World comparisons and recent trends |journal=Population and Societies |volume=391 |pages=1–4 |url=https://www.ined.fr/fichier/s_rubrique/247/english_391.en.pdf |url-status=dead |archive-url=https://web.archive.org/web/20160304091955/https://www.ined.fr/fichier/s_rubrique/247/english_391.en.pdf |archive-date=March 4, 2016}}</ref><ref name="Caselli">{{cite book| author = Graziella Caselli| author2 = Guillaume Wunsch| author3 = Daniel Courgeau| author4 = Jacques Vallin| title = Demography&nbsp;– Analysis and Synthesis: A Treatise in Population| publisher = ] | year = 2005 | pages = 490–501 | access-date = September 6, 2013 |isbn = 978-0-12-765660-1| url=https://books.google.com/books?id=nmgNXoiAiU4C&pg=PA491}}</ref> In the second group, the data indicated families encouraged daughters to delay marriage, and to abstain from sexual activity before that time. However, sons are encouraged to gain experience with older women or prostitutes before marriage. Age of men at sexual initiation in these societies is at lower ages than that of women; this group includes ] and Latin cultures (Portugal, Greece and Romania are noted) and such from ] (Brazil, ], and the ]). The study considered many Asian societies to also fall into this group, although matching data was only available from ].<ref name="Bozon" /><ref name="Caselli" /> In the third group, age of men and women at sexual initiation was more closely matched; there were two sub-groups, however. In non-Latin, Catholic countries (Poland and ] are mentioned), age at sexual initiation was higher, suggesting later marriage and reciprocal valuing of male and female virginity. The same pattern of late marriage and reciprocal valuing of virginity was reflected in ] and ]. The study considered China and Vietnam to also fall into this group, though data were not available.<ref name="Bozon" /><ref name="Caselli" /> In northern and eastern European countries, age at sexual initiation was lower, with both men and women involved in sexual intercourse before any union formation; the study listed Switzerland, Germany and the Czech Republic as members of this group.<ref name="Bozon" /><ref name="Caselli" />


Concerning United States data, tabulations by the ] report that the age of first sexual intercourse was 17.1 years for both males and females in 2010.<ref name="CDC abc_list_s">{{cite web|title=Key Statistics from the National Survey of Family Growth|access-date=February 9, 2013|publisher=] (CDC)|url=https://www.cdc.gov/nchs/nsfg/abc_list_s.htm}}</ref> The CDC stated that 45.5 percent of girls and 45.7 percent of boys had engaged in sexual activity by 19 in 2002; in 2011, reporting their research from 2006 to 2010, they stated that 43% of American unmarried teenage girls and 42% of American unmarried teenage boys have ever engaged in sexual intercourse.<ref name="CDC statistics">{{cite web|title=Teenagers in the United States: Sexual Activity, Contraceptive Use, and Childbearing, 2006–2010 National Survey of Family Growth|access-date=December 26, 2012|publisher=] (CDC)|url=https://www.cdc.gov/nchs/data/series/sr_23/sr23_031.pdf}}</ref> The CDC also reports that American girls will most likely lose their virginity to a boy who is 1 to 3 years older than they are.<ref name="CDC statistics"/> Between 1988 and 2002, the percentage of people in the U.S. who had sexual intercourse between the ages of 15 and 19 fell from 60 to 46 percent for never-married males, and from 51 to 46 percent for never-married females.<ref name="CDC sr23_024">{{cite web|title=Teenagers in the United States: Sexual Activity, Contraceptive Use, and Childbearing, 2002|access-date=February 9, 2013|publisher=] (CDC)|url=https://www.cdc.gov/nchs/data/series/sr_23/sr23_024.pdf}}</ref>
===Social and other behaviors===
], ]s,<ref>], "Bonobo Sex and Society", ''Scientific American'' (March 1995): 82-86.</ref> ]s and ]s<ref name="Dinitia">Dinitia Smith, "Central Park Zoo's gay penguins ignite debate", ''San Francisco Chronicle'' (February 7, 2004). Article is mainly about gay penguins but also mentions homosexuality in dolphins, and also says 'In bonobos, she noted: "you see expressions of sex outside the period when females are fertile."' Available online at http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2004/02/07/MNG3N4RAV41.DTL.</ref> are species known to engage in heterosexual behaviors even when the female is not in ], which is a point in her reproductive cycle suitable for successful impregnation. These species, and others, are also known to engage in homosexual behaviors.<ref name=Bagemihl/>


==Health effects==
In both humans and bonobos, the female undergoes relatively ] so that both male and female partners commonly do not know whether she is fertile at any given moment. One possible reason for this distinct biological feature may be formation of strong emotional bonds between sexual partners important for social interactions and, in the case of humans, long-term partnership rather than immediate sexual reproduction.<ref name="Diamond"/>


==={{anchor|Benefits}}Benefits===
Humans, bonobos and dolphins are all intelligent social animals, whose cooperative behavior proves far more successful than that of any individual alone. In these animals, the use of sex has evolved beyond reproduction apparently to serve additional social functions. Sex reinforces intimate social bonds between individuals to form larger social structures. The resulting cooperation encourages collective tasks that promote the survival of each member of the group.
In humans, sexual intercourse and sexual activity in general have been reported as having health benefits as varied as increased ] by increasing the body's production of ] and subsequent lower ],<ref name="Steptoe">{{cite book| author = Andrew Steptoe| author2 = Kenneth Freedland| author3 = J. Richard Jennings| author4 = Maria M. Llabre| author5 = Stephen B Manuck| author6 = Elizabeth J. Susman|author-link=Andrew Steptoe |author5-link=Stephen Manuck |title =Handbook of Behavioral Medicine: Methods and Applications| publisher = ] | year = 2010 | pages = 60–61 | access-date = December 7, 2014 |isbn = 978-0-387-09488-5| url =https://books.google.com/books?id=Si9TtI5AGIEC&pg=PA60}}</ref><ref name="Hornstein">{{cite book| author = Theresa Hornstein| author2 = Jeri Schwerin|title =Biology of Women| publisher = ] | year = 2012 | page = 205 | access-date = December 7, 2014 |isbn = 978-1-285-40102-7| url =https://books.google.com/books?id=ibgKAAAAQBAJ&pg=PA205}}</ref> and decreased risk of ].<ref name="Steptoe"/> Sexual intimacy and orgasms increase levels of the hormone ] (also known as "the love hormone"), which can help people bond and build trust.<ref name="Hornstein"/><ref name="Sigelman">{{cite book| author = Carol Sigelman| author2 = Elizabeth Rider|title =Life-Span Human Development| publisher = ] | year = 2011 | page = 452 | access-date = December 7, 2014 |isbn = 978-1-111-34273-9| url =https://books.google.com/books?id=8smBuRecmDsC&pg=PT480}}</ref> Oxytocin is believed to have a more significant impact on women than on men, which may be why women associate sexual attraction or sexual activity with romance and love more than men do.<ref name="Freberg"/> A long-term study of 3,500 people between ages 18 and 102 by clinical ] David Weeks indicated that, based on impartial ratings of the subjects' photographs, sex on a regular basis is associated with people looking significantly chronologically younger. However this does not imply causality.<ref>{{cite book|last=Northrup|first=Christiane|author-link=Christiane Northrup|title=Women's Bodies, Women's Wisdom: Creating Physical and Emotional Health and Healing|year=2010|publisher=Bantam|isbn=978-0-553-80793-6|page=232|url=https://books.google.com/books?id=V9S3keMnie8C&pg=PA232|access-date=October 21, 2015}}</ref>


Vaginal intercourse for the first time increases vaginal immune activity.<ref name="10.7554/eLife.78565">{{cite journal |last1=Hughes |first1=Sean M |last2=Levy |first2=Claire N |last3=Calienes |first3=Fernanda L |last4=Martinez |first4=Katie A |last5=Selke |first5=Stacy |last6=Tapia |first6=Kenneth |last7=Chohan |first7=Bhavna H |last8=Oluoch |first8=Lynda |last9=Kiptinness |first9=Catherine |last10=Wald |first10=Anna |last11=Ghosh |first11=Mimi |last12=Hardy |first12=Liselotte |last13=Ngure |first13=Kenneth |last14=Mugo |first14=Nelly R |last15=Hladik |first15=Florian |last16=Roxby |first16=Alison C |title=Starting to have sexual intercourse is associated with increases in cervicovaginal immune mediators in young women: a prospective study and meta-analysis |journal=eLife |date=October 25, 2022 |volume=11 |pages=e78565 |doi=10.7554/eLife.78565 |pmid=36281966 |pmc=9596159 |doi-access=free }}</ref>
] and others posit three potential advantages of intercourse in humans, which are not mutually exclusive: reproductive, relational, and recreational.<ref name="Diamond"/><ref>'']'': A Gourmet Guide to Lovemaking (1972)</ref> While the development of ] and other highly effective forms of ] in the mid- and late 20th century increased people's ability to segregate these three functions, they still overlap a great deal and in complex patterns. For example: A fertile couple may have intercourse while contracepting not only to experience sexual pleasure (recreational), but also as a means of emotional intimacy (relational), thus deepening their bonding, making their relationship more stable and more capable of sustaining children in the future (deferred reproductive). This same couple may emphasize different aspects of intercourse on different occasions, being playful during one episode of intercourse (recreational), experiencing deep emotional connection on another occasion (relational), and later, after discontinuing contraception, seeking to achieve pregnancy (reproductive, or more likely reproductive and relational).
==Health risks==
{{sectstub}}
In contrast to its benefits, sexual behavior can be a ]. ] is a relevant ] philosophy.<ref>{{cite web
| title = STI Epi Update: Oral Contraceptive and Condom Use
| url = http://www.phac-aspc.gc.ca/publicat/epiu-aepi/std-mts/std511_e.html
| publisher = '']''
| date = 1998-04-23
| accessdate = 2007-07-11}}</ref>


===Risks{{anchor|General risks}}===
==Sexual ethics and legality==
]s (STIs) are ], ]es or ] that are ] by sexual contact, especially vaginal, anal, or oral intercourse, or ].<ref name="Hoeger">{{cite book|vauthors=Hoeger W, HS, FA, HC|title=Principles and Labs for Fitness and Wellness| publisher = ] | year = 2016 | pages = 538–540|isbn = 978-1-337-09997-4| url =https://books.google.com/books?id=wdq5DQAAQBAJ}}</ref><ref name=Women2017>{{Cite web|url=https://www.womenshealth.gov/a-z-topics/sexually-transmitted-infections|title=Sexually transmitted infections|website=womenshealth.gov|language=en|access-date=December 8, 2017|date=February 22, 2017}}{{PD-notice}}</ref> Oral sex is less risky than vaginal or anal intercourse.<ref name="Gulanick">{{cite book|vauthors=Gulanick M, Myers JL |title=Nursing Care Plans - E-Book: Diagnoses, Interventions, and Outcomes| publisher=] |year=2016 |page=725|isbn=978-0-323-42810-1| url=https://books.google.com/books?id=NK2ADQAAQBAJ}}</ref> Many times, STIs initially do not cause symptoms, increasing the risk of unknowingly passing the infection on to a sex partner or others.<ref>{{cite book|vauthors=Murray PR, Rosenthal KS, Pfaller MA|title=Medical microbiology|date=2013|publisher=Mosby|location=St. Louis, MO|isbn=978-0-323-08692-9 |page=418|edition=7th|url=https://books.google.com/books?id=RBEVsFmR2yQC&pg=PA418 |url-status=live |archive-url=https://web.archive.org/web/20151201070705/https://books.google.com/books?id=RBEVsFmR2yQC&pg=PA418 |archive-date=December 1, 2015}}</ref><ref>{{cite book|last1=Goering|first1=Richard V.|title=Mims' medical microbiology |date=2012 |publisher=Saunders|location=Edinburgh|isbn=978-0-7234-3601-0 |page=245 |edition=5th |url=https://books.google.com/books?id=pzQayLEQ5mQC&pg=PA245}}</ref>
{{Refimprove|section|date=October 2008}}


There are 19 million new cases of sexually transmitted infections every year in the U.S.,<ref>{{cite web|title=STD Trends in the United States: 2010 National Data for Gonorrhea, Chlamydia, and Syphilis |url=https://www.cdc.gov/std/stats10/trends.htm |publisher=] |url-status=dead |archive-url=https://web.archive.org/web/20120326175627/https://www.cdc.gov/std/stats10/trends.htm |archive-date=March 26, 2012 |access-date=September 23, 2023}}</ref> and, in 2005, the World Health Organization (WHO) estimated that 448 million people aged 15–49 were infected per year with curable STIs (such as ], ] and ]).<ref name="WHO 2015">{{cite web| title=Sexually transmitted infections (STIs)|publisher=World Health Organization| url =https://www.who.int/mediacentre/factsheets/fs110/en/| access-date = June 20, 2015}}</ref> Some STIs can cause a ]; even if they do not, they increase the risk of both acquiring and passing on HIV up to ten-fold.<ref name="WHO 2015"/> ] can also be transmitted through sexual contact.<ref> Accessed May 27, 2010</ref> Globally, there are about 257 million chronic carriers of hepatitis B.<ref>{{cite web|title=Hepatitis B|url=https://www.who.int/news-room/fact-sheets/detail/hepatitis-b |publisher=] |date=July 18, 2018}}</ref> HIV is one of the world's leading infectious killers; in 2010, approximately 30 million people were estimated to have died because of it since the beginning of the epidemic. Of the 2.7 million new ] estimated to occur worldwide in 2010, 1.9 million (70%) were in ]. The World Health Organization also stated that the "estimated 1.2 million Africans who died of HIV-related illnesses in 2010 comprised 69% of the global total of 1.8 million deaths attributable to the epidemic."<ref name=WHO-HIV>{{cite web|title=HIV/AIDS|publisher=] |url=https://www.who.int/gho/hiv/en/index.html|access-date=September 15, 2012}}</ref> It is ], and while no cure has been found, it can be controlled by management ], and patients can enjoy healthy and productive lives.<ref name=WHO-2012>{{cite web|title=HIV/AIDS|url=https://www.who.int/mediacentre/factsheets/fs360/en/index.html|work=Fact sheet N° 360|publisher=]|access-date=September 8, 2012|date=July 2012}}</ref>
{{seealso|Sexual ethics}}
], 18th century]]
Unlike some other sexual activities, vaginal intercourse has rarely been made ] on ] grounds or by government authorities, as procreation is inherently essential to the continuation to the species or of any particular genetic line, which is considered to be a positive factor, and indeed, enables most societies to continue in the first place. Many of the cultures that had prohibited sexual intercourse entirely no longer exist; an exception is the ], a group that reached a size of about 6,000 full members in 1840, but ] had only four members left.<ref>{{cite news|title=The Last Ones Standing|author=Chase, Stacey|date=July 23, 2006|publisher=] |url=http://www.boston.com/news/globe/magazine/articles/2006/07/23/the_last_ones_standing/?page=full}}</ref> There are, however, many communities within cultures that prohibit their members to engage in any form of sex, especially members of religious orders and the priesthood in the ] and ]. Within some ideologies, coitus has been considered the only "acceptable" sexual activity. Relatively strict designations of "appropriate" and "inappropriate" sexual intercourse have been in human culture for hundreds of years. These legal or cultural restrictions may include:


In cases where infection is suspected, early medical intervention is highly beneficial in all cases. The CDC stated "the risk of HIV transmission from an infected partner through oral sex is much less than the risk of HIV transmission from anal or vaginal sex," but that "measuring the exact risk of HIV transmission as a result of oral sex is very difficult" and that this is "because most sexually active individuals practice oral sex in addition to other forms of sex, such as vaginal or anal sex, when transmission occurs, it is difficult to determine whether it occurred as a result of oral sex or other more risky sexual activities". They added that "several co-factors may increase the risk of HIV transmission through oral sex"; this includes ulcers, ], genital sores, and the presence of other STIs.<ref name="CDC, oral sex"/>
*Sex among partners who are not ] (this is sometimes referred to as ])
*Sex between a married person and someone to whom they are not married (called ] or ]).
*Sex between partners of the same sex (also called ]).
*Commercial sex (also called ]).
*Sex between a living human and a human corpse (also called ]).
*Sex between close relatives (also called ]).
*Adults having sex with children (depending on the country and its laws, also called ])
*Humans having sex with non-human animals (also called ]).
*Sex between members of different tribes, ethnic groups, or races, as in ] or the ] during periods of ] (also called ]).
* Sexual intercourse during a woman's menstrual period, as seen in ].


In 2005, the World Health Organization estimated that 123 million women become pregnant worldwide each year, and around 87 million of those pregnancies or 70.7% are unintentional. Approximately 46 million pregnancies per year reportedly end in induced ].<ref>{{cite web|title=Not Every Pregnancy is Welcome|url=https://www.who.int/whr/2005/chapter3/en/index3.html|archive-url=https://web.archive.org/web/20050414233054/http://www.who.int/whr/2005/chapter3/en/index3.html|url-status=dead|archive-date=April 14, 2005|work=The world health report 2005&nbsp;– make every mother and child count|publisher=]|access-date=December 6, 2011}}</ref> Approximately 6 million U.S. women become pregnant per year. Out of known pregnancies, two-thirds result in live births and roughly 25% in abortions; the remainder end in miscarriage. However, many more women become pregnant and miscarry without even realizing it, instead mistaking the miscarriage for an unusually heavy ].<ref name="Guttmacher 0">{{cite web|title=Get "In the Know": 20 Questions About Pregnancy, Contraception and Abortion |publisher=] |year=2005 |access-date=March 4, 2011 |url=http://www.guttmacher.org/in-the-know/index.html |url-status=deviated |archive-url=https://web.archive.org/web/20091223093547/http://www.guttmacher.org/in-the-know/index.html |archive-date=December 23, 2009 }}</ref> The U.S. ] rate fell by 27 percent between 1990 and 2000, from 116.3 pregnancies per 1,000 girls aged 15–19 to 84.5. This data includes live births, abortions, and fetal losses. Almost 1 million American teenage women, 10% of all women aged 15–19 and 19% of those who report having had intercourse, become pregnant each year.<ref name="Ventura">{{cite web|author=Ventura, SJ|author2=Abma, JC|author3=Mosher, WD|author4=Henshaw, S.|name-list-style=amp|title=Estimated pregnancy rates for the United States, 1990–2000: An Update. National Vital Statistics Reports, 52 (23)|publisher=]|date=November 16, 2007|access-date=March 4, 2011|url=https://www.cdc.gov/nchs/data/nvsr/nvsr52/nvsr52_23.pdf}}</ref>
Often a community adapts its legal definitions during ]s for settling disputes. For example, in 2003 the ] ruled that same-sex relations do not constitute ''sexual intercourse'', based on a 1961 definition from ], in ], and thereby an accused spouse in a divorce case was found not guilty of ''adultery'' based on this technicality.


Sexual activity can increase the expression of a ] factor called ] (delta FosB) in the ];<ref name="ΔFosB reward">{{cite journal |vauthors=Blum K, Werner T, Carnes S, Carnes P, Bowirrat A, Giordano J, Oscar-Berman M, Gold M | title = Sex, drugs, and rock 'n' roll: hypothesizing common mesolimbic activation as a function of reward gene polymorphisms | journal = Journal of Psychoactive Drugs | volume = 44 | issue = 1 | pages = 38–55 | year = 2012 | pmid = 22641964 | pmc = 4040958 | doi = 10.1080/02791072.2012.662112}}</ref><ref name="Natural and drug addictions">{{cite journal | author = Olsen CM | title = Natural rewards, neuroplasticity, and non-drug addictions | journal = Neuropharmacology | volume = 61 | issue = 7 | pages = 1109–1122 |date=December 2011 | pmid = 21459101 | pmc = 3139704 | doi = 10.1016/j.neuropharm.2011.03.010 }}</ref><ref name="Amph and sex addiction"><!--Supplemental primary source-->{{cite journal |vauthors=Pitchers KK, Vialou V, ], Laviolette SR, Lehman MN, Coolen LM | title = Natural and drug rewards act on common neural plasticity mechanisms with ΔFosB as a key mediator | journal = J. Neurosci. | volume = 33 | issue = 8 | pages = 3434–42 |date=February 2013 | pmid = 23426671 | pmc = 3865508 | doi = 10.1523/JNEUROSCI.4881-12.2013 }}</ref> consequently excessively frequent engagement in sexual activity on a regular (daily) basis can lead to the overexpression of ΔFosB, inducing an addiction to sexual activity.<ref name="ΔFosB reward" /><ref name="Natural and drug addictions" /><ref name="Amph and sex addiction" /> ] or ] is often considered an impulse control disorder or a behavioral addiction. It has been linked to atypical levels of dopamine, a neurotransmitter. This behavior is characterized by a fixation on sexual intercourse and disinhibition. It was proposed that this 'addictive behavior' be classified in ] as an impulsive–compulsive behavioral disorder. Addiction to sexual intercourse is thought to be genetically linked. Those having an addiction to sexual intercourse have a higher response to visual sexual cues in the brain. Those seeking ] will typically see a physician for pharmacological management and therapy.<ref name="Probstvan Eimeren2013">{{cite journal|last1=Probst |first1=Catharina C.|last2=van Eimeren|first2=Thilo|title=The Functional Anatomy of Impulse Control Disorders|journal=Current Neurology and Neuroscience Reports|volume=13|issue=10|pages=386|year=2013 |issn=1528-4042|doi=10.1007/s11910-013-0386-8|pmid=23963609|pmc=3779310}}</ref> One form of hypersexuality is ]. It is manifested by ] and hypersexuality and remains relatively rare.<ref name="GuilleminaultMiglis2014">{{cite journal|last1=Guilleminault|first1=Christian|last2=Miglis|first2=Mitchell|author1-link=Christian Guilleminault|title=Kleine-Levin syndrome: a review|journal=Nature and Science of Sleep|volume=6|pages=19–26|year=2014|issn=1179-1608|doi=10.2147/NSS.S44750|pmid=24470783|pmc=3901778 |doi-access=free }}</ref>
Most countries have ] laws specifying the minimum legal age for engaging in sexual intercourse. Sexual intercourse with a person against their will, or without their ], is referred to as ], and is considered a serious ] in many cultures around the world, including those found in ], northern and eastern ], and the ]. Sex, regardless of consent, with a person under the age of consent is often considered to be ] or ]. The age of consent varies from country to country and often by state or region; commonly, the age of consent is set anywhere between twelve and eighteen years of age, with sixteen years being the most common age the law sets. Sometimes, the age of consent is lowered for people near the same age wishing to participate in intercourse. For example, in ], the minimum age of consent for all couples is 16. However, the age of consent can go below 16 on the condition that the couple still are not 2 years of age apart. Religions may also set differing ages for consent, with Islam setting the age at puberty, which can vary from around 10 to 14. There are exceptions in the case of anal sex or people in a position of trust/authority.
== Religious and philosophical views ==
{{main|Religion and sexuality}}


], particularly due to ] complications, which is sometimes called ''coital death,'' ''coital sudden death'' or ''coital coronary.''<ref name="Kahn, Fawcett"/><ref name="Kipshidze">{{Cite book|author= Nicolas Kipshidze|author2= Jawad Fareed|author3= Patrick W. Serruys|author4= Jeff Moses | title = Textbook of Interventional Cardiovascular Pharmacology| year = 2007 | publisher = ] |page=505 | isbn = 978-0-203-46304-8| url=https://books.google.com/books?id=13g_niZy0usC&pg=PA505| access-date=October 21, 2015}}</ref><ref name="Dahabreh">{{cite journal|last=Dahabreh|first=Issa J. |title=Association of Episodic Physical and Sexual Activity With Triggering of Acute Cardiac Events. Systematic Review and Meta-analysis |journal=JAMA: The Journal of the American Medical Association|date=March 23, 2011|volume=305 |issue=12|pages=1225–33|doi=10.1001/jama.2011.336|pmid=21427375|pmc=5479331|quote=Acute cardiac events were significantly associated with episodic physical and sexual activity; this association was attenuated among persons with high levels of habitual physical activity.}}</ref> However, coital deaths are significantly rare.<ref name="Kipshidze"/> People, especially those who get little or no physical exercise, have a slightly increased risk of triggering a ] or ] when they engage in sexual intercourse or any vigorous physical exercise that is engaged in on a sporadic basis.<ref name="Dahabreh"/> Regular exercise reduces, but does not eliminate, the increased risk.<ref name="Dahabreh"/>
Modern humans, who date from approximately 400,000 years ago, have always reproduced by sexual intercourse. Modern religions and philosophies, on the other hand, are all less than 10,000 years old, and it is impossible to determine if there were earlier religious of philosophical views on sexual intercourse. Some religious traditions, such as fundamentalist Christianity, hold that the first humans came into being by an act of God and not through human sexual intercourse. That is, after each pair of animals or humans were created, they began reproducing through sexual intercourse. Others, such as Mormonism, hold that there is a Heavenly Father and Mother whose actions resulted in earthly children.


===Duration and genital complications===
Religious and philosophical viewpoints on sexual intercourse are varied. Some hold that person should engage in whatever sexual act they desire so long as it does not involve children, animals, or those who cannot or will not willingly consent to participate. Others hold that sexual intercourse is acceptable with an unwilling spouse (also known as "conjugal rites").
{{see also|Intravaginal ejaculation latency time|Coitus reservatus}}


Sexual intercourse, when involving a male participant, often ends when the male has ejaculated, and thus the partner might not have time to reach ].<ref name="Wincze">{{Cite book|author= John Wincze | title = Enhancing Sexuality : A Problem-Solving Approach to Treating Dysfunction| year = 2009 | publisher = ] |pages=56–60 | isbn = 978-0-19-971802-3| url=https://books.google.com/books?id=8YxbeHsgiGMC&pg=PA56}}</ref> In addition, ] (PE) is common, and women often require a substantially longer duration of stimulation with a sexual partner than men do before reaching an orgasm.<ref name="Weiten, 2011" /><ref name="Porst">{{cite book |author = Hartmut Porst |author2 = Jacques Buvat|title =Standard Practice in Sexual Medicine| publisher = ] | year = 2008|access-date=October 22, 2013 | page = 189|isbn = 978-1-4051-7872-3 |url=https://books.google.com/books?id=S4GJio79XOUC&pg=PA189}}</ref><ref name="Emmanuele">{{cite book|author1-link=Emmanuele A. Jannini|author = Emmanuele A. Jannini |author2 = Chris G. McMahon |author3 = Marcel D. Waldinger|title =Premature Ejaculation: From Etiology to Diagnosis and Treatment| publisher = ] | year = 2012|access-date=October 22, 2013 | pages = 159–162|isbn = 978-88-470-2646-9 |url=https://books.google.com/books?id=iCXF3sWtgegC&pg=PA159}}</ref> Scholars, such as Weiten et al., state that "many couples are locked into the idea that orgasms should be achieved only through intercourse ," that "the word ''foreplay'' suggests that any other form of sexual stimulation is merely preparation for the 'main event'" and that "because women reach orgasm through intercourse less consistently than men," they are likelier than men to ] to satisfy their sexual partners.<ref name="Weiten, 2011" />
]s support committed heterosexual relationships within marriage, though the particulars are varied and have changed over time.
]
In 1991, scholars from the Kinsey Institute stated, "The truth is that the time between penetration and ejaculation varies not only from man to man, but from one time to the next for the same man." They added that the appropriate length for sexual intercourse is the length of time it takes for both partners to be mutually satisfied, emphasizing that ] "found that 75 percent of men ejaculated within two minutes of penetration. But he didn't ask if the men or their partners considered two minutes mutually satisfying" and "more recent research reports slightly longer times for intercourse".<ref name="Reinisch">{{cite book | title = The Kinsey Institute New Report On Sex| publisher = ] | year = 1991 | pages = 129–130| access-date = August 30, 2012 |isbn = 978-0-312-06386-3| url = https://books.google.com/books?id=KsW6wPiXEd0C&pg=PA129 |author1=June M. Reinisch |author2=Ruth Beasley |author1-link=June Reinisch }}</ref> A 2008 survey of Canadian and American ] stated that the average time for heterosexual intercourse (coitus) was 7 minutes and that 1 to 2 minutes was too short, 3 to 7 minutes was adequate and 7 to 13 minutes desirable, while 10 to 30 minutes was too long.<ref name="Carroll"/><ref>{{cite journal |vauthors=Corty EW, Guardiani JM | title = Canadian and American Sex Therapists' Perceptions of Normal and Abnormal Ejaculatory Latencies: How Long Should Intercourse Last? | journal = The Journal of Sexual Medicine | volume = 5 | issue = 5 | pages = 1251–1256 | year = 2008 | pmid = 18331255 | doi = 10.1111/j.1743-6109.2008.00797.x }}</ref>


] is regular difficulty reaching orgasm after ample sexual stimulation, causing personal distress.<ref name="Bullough">{{cite book |author=Vern L Bullough |author2=Bonnie Bullough |author-link=Vern Bullough |author2-link=Bonnie Bullough | title = Human Sexuality: An Encyclopedia | publisher =]|page=32|year = 2014|access-date=December 6, 2014| isbn = 978-1-135-82502-7 |url =https://books.google.com/books?id=-cqlAgAAQBAJ&pg=PA32}}</ref> This is significantly more common in women than in men,<ref name="Rosenthal">{{cite book |first=Martha |last= Rosenthal| title = Human Sexuality: From Cells to Society | publisher =]|year = 2012|page=150|access-date=October 22, 2013| isbn = 978-0-618-75571-4 |url =https://books.google.com/books?id=d58z5hgQ2gsC&pg=PT170}}</ref><ref name="Weiner2">{{cite book |author =Irving B. Weiner |author2 =George Stricker |author3 =Thomas A. Widiger |author3-link=Thomas Widiger|title =Handbook of Psychology, Clinical Psychology| publisher = ] | year = 2012|access-date=October 22, 2013| pages = 172–175|isbn = 978-1-118-40443-0|url=https://books.google.com/books?id=A_NaK3cwQSsC&pg=PA172}}</ref> which has been attributed to the lack of ] with regard to women's bodies, especially in ] cultures, such as clitoral stimulation usually being key for women to orgasm.<ref name="Weiner2"/> The physical structure of coitus favors penile stimulation over clitoral stimulation; the location of the clitoris then usually necessitates manual or oral stimulation in order for the woman to achieve orgasm.<ref name="Weiten, 2011"/> Approximately 25% of women report difficulties with orgasm,<ref name="Carroll"/> 10% of women have never had an orgasm,<ref name="Plotnik">{{cite book |author1=Rod Plotnik |author2=Haig Kouyoumdjian |title =Introduction to Psychology| publisher = ] | year = 2010 | page = 344|isbn = 978-0-495-90344-4| quote= Inhibited female orgasm refers to a persistent delay or absence of orgasm after becoming aroused and excited. About 10% of women never reach orgasm...}}</ref> and 40% or 40–50% have either complained about sexual dissatisfaction or experienced difficulty becoming sexually aroused at some point in their lives.<ref name="Knoepp">{{cite journal |vauthors=Knoepp LR, Shippey SH, Chen CC, Cundiff GW, Derogatis LR, Handa VL | title = Sexual complaints, pelvic floor symptoms, and sexual distress in women over forty | journal = ] | volume = 7 | issue = 11 | pages = 3675–82 | year = 2010 | pmid = 20704643 | pmc = 3163299 | doi = 10.1111/j.1743-6109.2010.01955.x }}</ref>
Ancient ] and early ], allowed sexual relations between one male and more than one female (]), and Islam still does. The ] required that a brother have sexual intercourse with his brother's widowed, childless spouse so as to provide her children and forbade ] in such cases. Modern Judaism views sex and reproduction as the holiest of human acts, the act through which one can imitate God, the Creator.


] is involuntary tensing of the pelvic floor musculature, making coitus, or any form of penetration of the vagina, distressing, painful and sometimes impossible for women. It is a conditioned reflex of the pubococcygeus muscle, and is sometimes referred to as the ''PC muscle.'' Vaginismus can be hard to overcome because if a woman expects to experience pain during sexual intercourse, this can cause a muscle spasm, which results in painful sexual intercourse.<ref name="Weiner2"/><ref name="Ferri">{{cite book|author=Fred F. Ferri|title=Ferri's Clinical Advisor 2013,5 Books in 1, Expert Consult&nbsp;— Online and Print,1: Ferri's Clinical Advisor 2013|publisher=]|isbn=978-0-323-08373-7|year=2012|page=1134|access-date=November 29, 2014|url=https://books.google.com/books?id=OR3VERnvzzEC&pg=PA1134}}</ref> Treatment of vaginismus often includes both psychological and behavioral techniques, including the use of ].<ref name="Goldman">{{cite book |author= Marlene B. Goldman |author2= Rebecca Troisi |author2-link=Rebecca J. Troisi |author3= Kathryn M. Rexrode| title = Women and Health | publisher =]|page=351|year = 2012|access-date=December 6, 2014| isbn = 978-0-12-384979-3 |url =https://books.google.com/books?id=mavb4v8w8bsC&pg=PA351}}</ref> Additionally, the use of ] as a medical treatment for vaginismus has been tested and administered.<ref name="Comer">{{cite book |author= Ronald J. Comer| title = Fundamentals of Abnormal Psychology | publisher =]|page=338|year = 2010|access-date=December 6, 2014| isbn = 978-1-4292-1633-3 |url =https://books.google.com/books?id=y-FUzkLQ7GsC&pg=PA338}}</ref> Painful or uncomfortable sexual intercourse may also be categorized as ].<ref name="Goldman"/>
] views sex within marriage as something pleasurable, even a spiritual activity and a duty. Some Moslems hold that male martyrs for the Islamic faith will receive multiple virgin females as a reward in the afterlife.


Approximately 40% of males reportedly have some form of ] (ED) or impotence, at least occasionally.<ref name="Schouten">{{cite journal |vauthors=Schouten BW, Bohnen AM, Groeneveld FP, Dohle GR, Thomas S, Bosch JL | title = Erectile dysfunction in the community: trends over time in incidence, prevalence, GP consultation and medication use—the Krimpen study: trends in ED | journal = J Sex Med | volume = 7 | issue = 7 | pages = 2547–53 | date = July 2010 | pmid = 20497307 | doi = 10.1111/j.1743-6109.2010.01849.x }}</ref> Premature ejaculation has been reported to be more common than erectile dysfunction, although some estimates suggest otherwise.<ref name="Porst"/><ref name="Emmanuele"/><ref name="Schouten" /> Due to various meanings of the disorder, estimates for the prevalence of premature ejaculation vary significantly more than for erectile dysfunction.<ref name="Porst" /><ref name="Emmanuele" /> For example, the ] states, "Estimates vary, but as many as 1 out of 3 men may be affected by at some time."<ref name="Premature ejaculation">{{cite web|url=http://www.mayoclinic.com/health/premature-ejaculation/DS00578|title=Premature ejaculation|publisher=].com|access-date=March 2, 2007}}</ref> Further, "Masters and Johnson speculated that premature ejaculation is the most common sexual dysfunction, even though more men seek therapy for erectile difficulties" and that this is because "although an estimated 15 percent to 20 percent of men experience difficulty controlling rapid ejaculation, most do not consider it a problem requiring help, and many women have difficulty expressing their sexual needs".<ref name="Reinisch"/> The ] (AUA) estimates that premature ejaculation could affect 21 percent of men in the United States.<ref name="auanet.org">{{cite web|title=Guideline on the pharmacologic management of premature ejaculation|publisher=]|year=2004|access-date=October 12, 2013|url=http://www.auanet.org/common/pdf/education/clinical-guidance/Premature-Ejaculation.pdf|url-status=dead|archive-url=https://web.archive.org/web/20160303170443/http://www.auanet.org/common/pdf/education/clinical-guidance/Premature-Ejaculation.pdf|archive-date=March 3, 2016}}</ref>
] views sex in marriage as holy. It affirms that everything God created, including sex, is good. As there is no single central source of truth and doctrine in the largest Abrahamic traditions, there is wide variation of opinion and teaching about sexual intercourse within each, with some religious communities limiting sexual activity strictly to intercourse and others making practically no pronouncements on sex at all.


For those whose impotence is caused by medical conditions, prescription drugs such as ], ], and ] are available. However, doctors caution against the unnecessary use of these drugs because they are accompanied by serious risks such as increased chance of heart attack.<ref name="Greenberg ED">{{cite book |author= Jerrold S Greenberg |author2= Clint E. Bruess |author3=Sara B. Oswalt | title = Exploring the Dimensions of Human Sexuality | publisher =]|page=633|year = 2010|access-date=December 8, 2014| isbn = 978-0-7637-9740-9 |url = https://books.google.com/books?id=6b36v8JHznIC&pg=PA633}}</ref> The ] (SSRI) and antidepressant drug ] has been used to treat premature ejaculation.<ref name="Balon">{{cite book |author=Richard Balon |author2=Robert Taylor Segraves| title = Clinical Manual of Sexual Disorders | publisher =]|page=292|year = 2009|access-date=December 6, 2014| isbn = 978-1-58562-905-3 |url =https://books.google.com/books?id=YuP3Hb0TMLQC&pg=PA292}}</ref> In clinical trials, those with PE who took dapoxetine experienced sexual intercourse three to four times longer before orgasm than without the drug.<ref name="Architectural Press">{{cite book| title = The Architects' Journal |volume=221 |issue=17–21 | publisher =]|page=16|year = 2005|access-date=December 6, 2014|url =https://books.google.com/books?id=7HlNAAAAYAAJ&q=The+Architects%27+Journal,+Volume+221,+Issues+17-21}}</ref> Another ejaculation-related disorder is ], which can be caused as an unwanted side effect of antidepressant medications such as ]; however, all SSRIs have ejaculation-delaying effects, and fluvoxamine has the least ejaculation-delaying effects.<ref name="Balon2">{{cite book |author= Richard Balon |author2= Robert Taylor Segraves| title = Clinical Manual of Sexual Disorders | publisher =]|page=281|year = 2009|access-date=December 6, 2014| isbn = 978-1-58562-905-3 |url =https://books.google.com/books?id=YuP3Hb0TMLQC&pg=PA281}}</ref>
] has varied views about sexuality, but Hindu society, in general, perceives both pre-marital and extramarital sex to be immoral and shameful, notwithstanding popular culture. The ] is a well-known product of Hindu society that extols the benefits of sexual intercourse.


Sexual intercourse often remains possible after major medical treatment of the reproductive organs and structures. This is especially true for women. Even after extensive gynecological surgical procedures (such as ], ], ], ], ], ] surgery, abscess removal, ], ] reduction, ], ] and radiological cancer treatments and chemotherapy), sexual intercourse can continue. Reconstructive surgery remains an option for women who have experienced benign and malignant conditions.<ref name="Hoffman2012">{{cite book | last = Hoffman | first = Barbara | title = Williams gynecology | edition = 2nd | publisher = McGraw-Hill Medical |page=65 |location = New York | year = 2012 | isbn = 978-0-07-171672-7 }}</ref> Men and women who have underwent extensive surgery should consult their medical team to understand how their treatment or surgery affects sex and how long they should wait before having sexual intercourse after a surgery.<ref>{{Cite web |date=2017-09-22 |title=Sexual Health Issues in Men and Cancer Treatment - Side Effects - NCI |url=https://www.cancer.gov/about-cancer/treatment/side-effects/sexuality-men |access-date=2024-10-21 |website=www.cancer.gov |language=en}}</ref><ref>{{Cite web |title=Sexuality and intimacy |url=https://www.cancer.org.au/cancer-information/cancer-side-effects/sexuality-and-intimacy |access-date=2024-10-21 |website=www.cancer.org.au}}</ref><!--pages 1020-1348-->
] ethics, in its most common formulation, holds that one should neither be attached to nor crave sensual pleasure. Some Asian societies shaped by Buddhist traditions take a strong ethical stand on sexual behavior. In the ], sexual relationships are permitted only between a husband and wife.


===Disabilities and other complications===
]s, with an emphasis on strong interpersonal ethics, do not place boundaries on the occurrence of sexual intercourse among consenting adults other than the vows that individuals may have taken voluntarily.
{{main| Sexuality and disability}}


Obstacles that those with ] face with regard to engaging in sexual intercourse include pain, ], fatigue, ], stiffness, functional impairment, anxiety, reduced ], hormonal imbalance, and drug treatment or side effects. Sexual functioning has been regularly identified as a neglected area of the quality of life in patients with ].<ref name="Tristano2014">{{cite journal|last1=Tristano|first1=Antonio G|title=Impact of rheumatoid arthritis on sexual function|journal=World Journal of Orthopedics|volume=5|issue=2|pages=107–11|year=2014|issn=2218-5836|doi=10.5312/wjo.v5.i2.107|pmid=24829873|pmc=4017303 |doi-access=free }}</ref> For those that must take opioids for pain control, sexual intercourse can become more difficult.<ref name="DeyoVon Korff2015">{{cite journal|last1=Deyo|first1=R. A.|last2=Von Korff|first2=M.|last3=Duhrkoop|first3=D.|title=Opioids for low back pain|journal=BMJ|volume=350|issue= |year=2015|pages=g6380|issn=1756-1833|doi=10.1136/bmj.g6380|pmid=25561513|pmc=6882374}}</ref> Having a ] can also largely impact on the ability to engage in sexual intercourse.<ref name="HersonPalmateer2012">{{cite journal|last1=Herson|first1=Paco S.|last2=Palmateer|first2=Julie|last3=Hurn|first3=Patricia D.|title=Biological Sex and Mechanisms of Ischemic Brain Injury|journal=Translational Stroke Research|volume=4|issue=4|year=2012|pages=413–419|issn=1868-4483|doi=10.1007/s12975-012-0238-x|pmc=3733393|pmid=23930140}}</ref> Although disability-related pain, including as a result of ], and mobility impairment can hamper sexual intercourse, in many cases, the most significant impediments to sexual intercourse for individuals with a disability are psychological.<ref name="Falvo">{{cite book |author=Donna Falvo| title = Medical and Psychosocial Aspects of Chronic Illness and Disability | publisher =]|page=367|year = 2013|access-date=December 7, 2014| isbn = 978-1-4496-9442-5 |url =https://books.google.com/books?id=SdM6FsykfWAC&pg=PA367}}</ref> In particular, people who have a disability can find sexual intercourse daunting due to issues involving their ] as a sexual being, or a partner's discomfort or perceived discomfort.<ref name="Falvo"/> Temporary difficulties can arise with ], as alcohol can initially increase interest through disinhibition but decrease capacity with greater intake; however, disinhibition can vary depending on the culture.<ref name="WHO Risks">{{cite book|title=Alcohol Use and Sexual Risk Behaviour: A Cross-cultural Study in Eight Countries|publisher=]|year=2005|pages=135 pages|access-date = March 30, 2013 |isbn = 978-92-4-156289-8| url =https://books.google.com/books?id=fZ1eBPIIr48C }}</ref><ref name="Aggleton">{{cite book |author=Peter Aggleton |author2=Andrew Ball |author3=Purnima Mane |author3-link=Purnima Mane | title = Sex, Drugs and Young People: International Perspectives | publisher =]|pages=130–133|year = 2013|access-date=December 7, 2014| isbn = 978-1-134-33309-7 |url = https://books.google.com/books?id=dWknAAAAQBAJ&pg=PA130}}</ref>
] religions tend to be positive about sexuality among consenting adults.


People with ] also are subject to challenges in participating in sexual intercourse. This can include the lack of a knowledgeable healthcare provider trained and experienced in counseling those with ] on sexual intercourse. Those with intellectual disabilities may have hesitations regarding the discussion of the topic of sex, a lack of sexual knowledge and limited opportunities for sex education.<ref>{{cite journal |last1=Medina-Rico |first1=Mauricio |last2=López-Ramos |first2=Hugo |last3=Quiñonez |first3=Andrés |title=Sexuality in People with Intellectual Disability: Review of Literature |journal=Sexuality and Disability |date=September 1, 2018 |volume=36 |issue=3 |pages=231–248 |doi=10.1007/s11195-017-9508-6 |s2cid=255009541 |url=https://link.springer.com/article/10.1007/s11195-017-9508-6 |language=en |issn=1573-6717}}</ref> In addition there are other barriers such as a higher prevalence of sexual abuse and assault. These crimes often remain underreported. There remains a lack of "dialogue around this population's human right to consensual sexual expression, undertreatment of menstrual disorders, and legal and systemic barriers". Women with intellectual disability may lack sexual health care and sex education. They may not recognize sexual abuse. Consensual sexual intercourse is not always an option for some. Those with intellectual disability may have limited knowledge and access to contraception, screening for sexually transmitted infections and cervical cancer.<ref name="GreenwoodWilkinson2013">{{cite journal|last1=Greenwood|first1=Nechama W.|last2=Wilkinson|first2=Joanne|title=Sexual and Reproductive Health Care for Women with Intellectual Disabilities: A Primary Care Perspective|journal=International Journal of Family Medicine|volume=2013|year=2013|pages=1–8|issn=2090-2042|doi=10.1155/2013/642472|pmid=24455249|pmc=3876698|doi-access=free}}</ref>
] In his '']'', ], who first worked on his ideas as a Polish philosopher in '']'', taught that marital sexual intercourse is the best image of God who is love, for he sees the human body as the only one capable of making the invisible &mdash; the spiritual and the divine &mdash; visible.<ref>Karol Woytyla, Love and Responsibility, San Francisco, Ignatius Press 1993</ref> He said that human beings were created by God who is love for a purpose: to be loving persons who freely choose to love, to give themselves as persons who express their self-giving through their bodies. Thus, sexual intercourse between husband and wife is a ] of their total mutual self-donation, and further fosters, strengthens and enriches it not just for the present but also for the future. For John Paul II, "The body, and it alone, is capable of making visible what is invisible: the spiritual and divine." He says there is no other more perfect ] of the unity and communion of God in mutual love than the sexual act of a married couple, whereby they give themselves in a total way &mdash; exclusively to one another, and up to end of their lives, and in a fruitfully generous way by participating in the ] of new human beings. Through this perspective, he understands the immorality of extra marital sex. It falsifies the language of the human body, a language of total love worthy of persons by using the body for selfish ends, thus treating embodied ]s as ]s and objects, rather than dealing with human bodies with the ] and love that persons, incarnate spirits and images of God deserve. John Paul II stresses that there is great ] in sexual love when done in ] with the human values of freely chosen total commitment and self-giving. For him, this sexual love is a form of ], an experience of the ].<ref>Theology of Marriage and Celibacy, Boston, St. Paul Books and Media 1986</ref><ref>{{cite web | url=http://catholiceducation.org/articles/sexuality/se0109.html|author=Christopher West| work=Catholic Education Resource Center | title=What is the Theology of the Body & Why is it Changing so Many Lives? | accessdate=2009-09-29}}</ref>


==Social effects==
Catholicism forbids its members from engaging in forms of sexual expression such as masturbation and oral sex, and the use of contraception is forbidden.
{{See also|Human mating strategies|Pair bond}}
Though the official Catholic teaching on sexual intercourse is consistent with the statements of John Paul II, thousands of cases of ] of minors by Catholic priests were brought to light during his papacy.


===Adults===
], the philosophy espoused by ], like other similar movements including ] holds that people should pursue the lifestyle that makes them happiest so long as others are not hurt.
Sexual intercourse may be for reproductive, relational, or recreational purposes.<ref name="Harvey J">{{cite book| first1=John H. |last1=Harvey |first2=Amy |last2=Wenzel |first3=Susan |last3=Sprecher|title =The Handbook of Sexuality in Close Relationships|publisher = ] | year = 2004 | pages = 172–173|isbn =1-135-62470-4|url=https://books.google.com/books?id=qsl4AgAAQBAJ}}</ref> It often plays a strong role in ].<ref name="Freberg"/> In many societies, it is normal for couples to have sexual intercourse while using some method of birth control, sharing pleasure and strengthening their emotional bond through sexual activity even though they are deliberately avoiding pregnancy.<ref name="Freberg"/>

In humans and ]s, the female undergoes relatively ] so that male and female partners commonly do not know whether she is fertile at any given moment. One possible reason for this distinct biological feature may be formation of strong emotional bonds between sexual partners important for social interactions and, in the case of humans, long-term partnership rather than immediate sexual reproduction.<ref name="Reis">{{Cite book|author= Harry T. Reis|author2= Susan Sprecher |author-link=Harry Reis | title = Encyclopedia of Human Relationships |volume=1| year = 2009 | publisher = ] |pages=541–543 | isbn = 978-1-4129-5846-2| url=https://books.google.com/books?id=3EkOwvSAtL4C&pg=PA541}}</ref>

] due to the lack of sexual intercourse is associated with increased risk of ] and relationship dissolution, especially for men.<ref name="Munck">{{cite book| author = Victor C. De Munck|title =Romantic Love and Sexual Behavior: Perspectives from the Social Sciences|publisher = ] | year = 1998 | pages = 148–149 | access-date = December 9, 2014 |isbn = 978-0-275-95726-1| url =https://books.google.com/books?id=I78VnFoINgQC&pg=PA148}}</ref><ref name="Howe">{{cite book| author = Tasha R. Howe|title =Marriages and Families in the 21st Century: A Bioecological Approach|publisher = ] | year = 2011 | page = 411 | access-date = December 9, 2014 |isbn = 978-1-4051-9501-0| url =https://books.google.com/books?id=UHaLL0pYwhMC&pg=PA411}}</ref><ref name="Fine">{{cite book|author1=Mark A Fine |author2=John H. Harvey |title =Handbook of Divorce and Relationship Dissolution|publisher = ] | year = 2013 | page = 160 | access-date = December 9, 2014 |isbn = 978-1-317-82421-3| url =https://books.google.com/books?id=wGZlAgAAQBAJ&pg=PA160}}</ref> Some research, however, indicates that general dissatisfaction with ] for men results if their wives ] with, erotically kissed or became romantically or sexually involved with another man (]),<ref name="Munck"/><ref name="Howe"/> and that this is especially the case for men with a lower emotional and composite marital satisfaction.<ref name="Fine"/> Other studies report that the lack of sexual intercourse does not significantly result in divorce, though it is commonly one of the various contributors to it.<ref name="Reinisch2">{{cite book| author = June M. Reinisch| author2 = Ruth Beasley| author-link = June Reinisch | title = The Kinsey Institute New Report On Sex| publisher = ] | year = 1991 | page = 74| access-date = December 9, 2014 |isbn = 978-0-312-06386-3| url =https://books.google.com/books?id=KsW6wPiXEd0C&pg=PA74}}</ref><ref name="Schwartz2">{{cite book| author = Pepper Schwartz| author2 = Virginia Rutter| author-link=Pepper Schwartz | author2-link=Virginia Rutter |title =The Gender of Sexuality|publisher = ] | year = 1998 | page = 129 | access-date = December 9, 2014 |isbn = 978-0-8039-9042-5| url =https://books.google.com/books?id=7bWlvcpYGUcC&pg=PA129}}</ref> According to the 2010 National Survey of Sexual Health and Behavior (NSSHB), men whose most recent sexual encounter was with a relationship partner reported greater arousal, greater pleasure, fewer problems with erectile function, orgasm, and less pain during the event than men whose last sexual encounter was with a non-relationship partner.<ref name="Yarber">{{cite book| author = William Yarber| author2 = Barbara Sayad| author3 = Bryan Strong| author3-link = Bryan Strong|title =Human Sexuality: Diversity in Contemporary America|edition =Eighth|publisher = ] | year = 2012 | page = 445 | access-date = December 9, 2014 |isbn = 978-0-07-743525-7| url =https://books.google.com/books?id=EWz7twAACAAJ&q=Human+Sexuality:+Diversity+in+Contemporary+America}}</ref>

For women, there is often a complaint about the lack of their spouses' sexual spontaneity. Decreased sexual activity among these women may be the result of their perceived failure to maintain ideal ] or because their sexual partners' health issues have hindered sexual intercourse.<ref name="Montemurro">{{cite book| author = Beth Montemurro|title =Deserving Desire: Women's Stories of Sexual Evolution|publisher = ] | year = 2014 | page = 169 | access-date = December 9, 2014 |isbn = 978-0-8135-7306-9| url =https://books.google.com/books?id=1XVYBQAAQBAJ&pg=PT169}}</ref> Some women express that their most satisfying sexual experiences entail being connected to someone, rather than solely basing satisfaction on orgasm.<ref name="Wincze"/><ref name="Gurian">{{cite book| author = Michael Gurian| author-link=Michael Gurian|title =The Wonder of Aging: A New Approach to Embracing Life After Fifty|publisher = ] | year = 2013 | page = 178 | access-date = December 9, 2014 |isbn = 978-1-4767-0671-9| url =https://books.google.com/books?id=XyS5ebuXJWgC&pg=PT178}}</ref> With regard to divorce, women are more likely to divorce their spouses for a ] or various infidelities if they are in less cooperative or high-conflict marriages.<ref name="Fine"/>

Research additionally indicates that non-married couples who are ] engage in sexual intercourse more often than married couples, and are more likely to participate in sexual activity outside of their sexual relationships; this may be due to the "]" effect (the newness or novelty of sexual intercourse with the partner), since sexual intercourse is usually practiced less the longer a couple is married, with couples engaging in sexual intercourse or other sexual activity once or twice a week, or approximately six to seven times a month.<ref name="Strong2">{{cite book| author = Bryan Strong| author2 = Theodore Cohen |author-link=Bryan Strong|title =The Marriage and Family Experience: Intimate Relationships in a Changing Society|publisher = ] | year = 2013 | page = 212 | access-date = December 9, 2014 |isbn =978-1-285-53189-2| url =https://books.google.com/books?id=6ZIWAAAAQBAJ&pg=PT237}}</ref> ] also affects the frequency of sexual intercourse, as older people generally engage in sexual intercourse less frequently than younger people do.<ref name="Strong2"/>

===Adolescents===
{{Main|Adolescent sexuality}}
Adolescents commonly use sexual intercourse for relational and recreational purposes, which may negatively or positively impact their lives. For example, while ] may be welcomed in some cultures, it is also commonly disparaged, and research suggests that the ] for children puts pressure on children and teenagers to act like adults before they are emotionally or cognitively ready.<ref name="sex lives3">{{cite book| title=The Sex Lives of Teenagers| isbn=978-0-452-28260-5| last=Ponton| first=Lynn| author-link=Lynn Ponton| year=2000| page=| publisher=]| url=https://archive.org/details/sexlivesofteenag00lynn/page/3}}</ref> Some studies have concluded that engaging in sexual intercourse leaves adolescents, especially girls, with higher levels of stress and depression, and that girls may be likelier to engage in sexual risk (such as sexual intercourse without the use of a condom),<ref name="DiClemente">{{cite book| author = Ralph J. DiClemente| author2 = John S. Santelli| author3 = Richard A. Crosby|title = Adolescent Health: Understanding and Preventing Risk Behaviors| publisher = ] | year = 2009 | pages = 521–522| access-date = December 7, 2014 |isbn = 978-0-470-45279-0| url =https://books.google.com/books?id=KcrwY8eCwcQC&pg=PT521}}</ref><ref name="Abaied">{{cite book| author = Jamie L Abaied| author2 = Deepika Anand| author3 = Tracey L Auster| author4 = Daniel BE|title =The Oxford Handbook of Depression and Comorbidity| publisher = ] | year = 2014 | page = 450 | access-date = December 7, 2014 |isbn = 978-0-19-979700-4| url =https://books.google.com/books?id=hzpsAwAAQBAJ&pg=PA450}}</ref> but it may be that further research is needed in these areas.<ref name="Abaied"/> In some countries, such as the United States, ] and ] curricula are available to educate adolescents about sexual activity; these programs are controversial, as debate exists as to whether teaching children and adolescents about sexual intercourse or other sexual activity should only be left up to parents or other ]s.<ref name="Ryan">{{cite book| author =Kevin Ryan| author2 =James Cooper|title =Those Who Can, Teach|publisher = ] | year = 2008 | page = 110 | access-date = December 9, 2014 |isbn = 978-0-547-20488-8| url =https://books.google.com/books?id=rqmdR6Xrgq8C&pg=PA110}}</ref>

Some studies from the 1970s through 1990s suggested an association between ] and sexual intercourse among adolescents,<ref name="Lerner 2">{{cite book| first1 = Richard M. | last1 = Lerner | first2 = Daniel F. | last2 = Perkins | name-list-style = vanc |title = Social Interactions in Adolescence and Promoting Positive Social Contributions of Youth| publisher = ] | year = 1999 | page = 124| access-date = April 14, 2017 |isbn = 978-0-8153-3295-4| url =https://books.google.com/books?id=BunEIQylaJAC&pg=PA124}}</ref> while other studies, from the 1980s and 1990s, reported that the research generally indicates little or no relationship between self-esteem and sexual activity among adolescents.<ref name="Kowalski">{{cite book |vauthors=Kowalski RM, Leary MR |title =The Interface of Social and Clinical Psychology: Key Readings| publisher = ] | year = 2004 | page = 121| access-date = April 14, 2017 |isbn = 978-1-84169-087-2| url =https://books.google.com/books?id=qkEdaQ4heGgC&pg=PA121}}</ref> By the 1990s, the evidence mostly supported the latter,<ref name="Kowalski"/> and further research has supported little or no relationship between self-esteem and sexual activity among adolescents.<ref name="Guindon">{{cite book| author =Mary H. Guindon|title =Self-Esteem Across the Lifespan: Issues and Interventions| publisher = ] | year = 2009 | page = 147| access-date = April 14, 2017 |isbn = 978-1-84169-087-2| url =https://books.google.com/books?id=EcoPo06GYCMC&pg=PA147}}</ref><ref name="Lisa Arai">{{cite book| author =Lisa Arai|title =Teenage Pregnancy: The Making and Unmaking of a Problem| publisher = ] | year = 2009 | page = 147| access-date = April 14, 2017 |isbn = 978-1-84742-074-9| url =https://books.google.com/books?id=qzOguz7GqNoC&pg=PA32}}</ref> Scholar Lisa Arai stated, "The idea that early sexual activity and pregnancy is linked to low self-esteem became fashionable in the latter half of the 20th century, particularly in the US," adding that, "Yet, in a systematic review of the relationship between self-esteem and teenagers' sexual behaviours, attitudes and intentions (which analyzed findings from 38 publications) 62% of behavioral findings and 72% of the attitudinal findings exhibited no statistically significant associations (Goodson et al, 2006)."<ref name="Lisa Arai"/> Studies that do find a link suggest that non-virgin boys have higher self-esteem than virgin boys and that girls who have low self-esteem and poor ] are more prone to risk-taking behaviors, such as unprotected sex and ].<ref name="Lerner 2"/><ref name="Guindon"/><ref name="Lisa Arai"/>

Psychiatrist ] wrote, "All adolescents have sex lives, whether they are sexually active with others, with themselves, or seemingly not at all", and that viewing adolescent sexuality as a potentially positive experience, rather than as something inherently dangerous, may help young people develop healthier patterns and make more positive choices regarding sexual activity.<ref name="sex lives3" /> Researchers state that long-term romantic relationships allow adolescents to gain the skills necessary for high-quality relationships later in life.<ref>Madsen S., Collins W. A. (2005). Differential predictions of young adult romantic relationships from transitory vs. longer romantic experiences during adolescence. Presented at ''Biennial Meeting of the Society for Research on Child Development'', Atlanta, Georgia.</ref> Overall, positive romantic relationships among adolescents can result in long-term benefits. High-quality romantic relationships are associated with higher commitment in early adulthood,<ref>{{ill|Seiffge-Krenke I.|de|Inge Seiffge-Krenke}}, Lang J. (2002). Forming and maintaining romantic relations from early adolescence to young adulthood: evidence of a developmental sequence. Presented at 19th ''Biennial Meeting of the Society for Research on Adolescence'', New Orleans, Louisiana.</ref> and are positively associated with social competence.<ref>{{cite journal |vauthors=Pearce MJ, Boergers J, Prinstein MJ | s2cid = 154577 | title = Adolescent obesity, overt and relational peer victimization, and romantic relationships | journal = Obesity Research | volume = 10 | issue = 5 | pages = 386–93 | year = 2002 | pmid = 12006638 | doi = 10.1038/oby.2002.53 | doi-access = }}</ref><ref>{{cite journal |vauthors=Zimmer-Gembeck MJ, Siebenbruner J, Collins WA | title = A prospective study of intraindividual and peer influences on adolescents' heterosexual romantic and sexual behavior | journal = Archives of Sexual Behavior | volume = 33 | issue = 4 | pages = 381–394 | year = 2004 | pmid = 15162084 | doi = 10.1023/B:ASEB.0000028891.16654.2c | s2cid = 1054833 }}</ref>

==Ethical, religious, and legal views==
===General===
{{See also|Sexual ethics|Religion and sexuality|Sex and the law}}
]]]
While sexual intercourse, as coitus, is the natural mode of reproduction for the human species, humans have intricate moral and ethical guidelines which regulate the practice of sexual intercourse and vary according to ] and governmental laws. Some governments and religions also have strict designations of what they consider appropriate and inappropriate sexual behavior, which include restrictions on the types of sex acts which are permissible. A historically prohibited or regulated sex act is anal sex.<ref>] Dishonorable Passions: Sodomy Laws in America, 1861–2003. (2008) Viking Adult. {{ISBN|0-670-01862-7}}</ref><ref>Noelle N. R. Quenivet. Sexual Offenses in Armed Conflict & International Law. (2005) Hotei Publishing. {{ISBN|1-57105-341-7}}</ref>

===Sexual offenses===
Sexual intercourse with a person against their will, or without their ], is ], but may also be called '']''; it is considered a serious ] in most countries.<ref name="Sex and Society">{{cite book|author=Marshall Cavendish Corporation | title = Sex and Society | publisher = ] | year = 2010 | pages = 143–144 | access-date = August 25, 2013|isbn = 978-0-7614-7906-2|url =https://books.google.com/books?id=aVDZchwkIMEC&pg=PA143}}</ref><ref name="Greenberg2">{{cite book|author=Jerrold S. Greenberg|author2=Clint E. Bruess|author3=Sarah C. Conklin| title = Exploring the Dimensions of Human Sexuality| publisher = ] | year = 2010 | page = 515 | access-date = August 25, 2013|isbn = 978-0-7637-7660-2|url =https://books.google.com/books?id=1NC5R0RozBYC&pg=PA515}}</ref> More than 90% of rape victims are female, 99% of rapists male, and only about 5% of rapists are strangers to the victims.<ref name="Greenberg2"/>

Most countries have ] laws which set the minimum legal age with whom an older person may engage in sexual intercourse, usually set at 16 to 18, but ranges from 12 to 20, years of age. In some societies, an age of consent is set by non-statutory custom or tradition.<ref name="Kinnear">{{cite book|author=Karen L. Kinnear| title = Childhood Sexual Abuse: A Reference Handbook| publisher = ] | year = 2007 | page = 89 | access-date = August 25, 2013|isbn = 978-1-85109-905-4|url =https://books.google.com/books?id=V1rogCrcOMwC}}</ref> Sex with a person under the age of consent, regardless of their stated consent, is often considered sexual assault or ] depending on differences in ages of the participants. Some countries treat any sex with a person of diminished or insufficient mental capacity to give consent, regardless of age, as rape.<ref>{{cite journal |last=Reed|first=E. J.|title=Criminal Law and the Capacity of Mentally Retarded Persons to Consent to Sexual Activity |journal=] |year=1997|volume=83|issue=4 |pages=799–827|jstor=1073749|doi=10.2307/1073749}}</ref>
] depiction of rape]]
Robert Francoeur et al. stated that "prior to the 1970s, rape definitions of sex often included only penile-vaginal sexual intercourse."<ref name="Francoeur">{{cite book | title = The Continuum Complete International Encyclopedia of Sexuality | publisher = ] | year = 2004 | page = 173 | access-date = April 30, 2013|isbn = 978-0-8264-1488-5| url =https://books.google.com/books?id=PQMTzc6y8ZAC&pg=PA173 | first1 = Robert T. | last1 = Francoeur | author1-link = Robert T. Francoeur | first2 = Raymond J. | last2 = Noonan | first3 = Beldina | last3 = Opiyo-Omolo | name-list-style = vanc }}</ref> Authors Pamela J. Kalbfleisch and Michael J. Cody stated that this made it so that if "sex means penile-vaginal intercourse, then rape means forced penile-vaginal intercourse, and other sexual behaviors&nbsp;– such as fondling a person's genitals without her or his consent, forced oral sex, and same-sex coercion&nbsp;– are not considered rape"; they stated that "although some other forms of forced sexual contact are included within the legal category of sodomy (e.g., anal penetration and oral-genital contact), many unwanted sexual contacts have no legal grounding as rape in some states".<ref name="Kalbfleisch"/> Ken Plumber argued that the legal meaning "of rape in most countries is unlawful sexual intercourse which means the penis must penetrate the vagina" and that "other forms of sexual violence towards women such as forced oral sex or anal intercourse, or the insertion of other objects into the vagina, constitute the 'less serious' crime of sexual assault".<ref name="Plummer">{{cite book| author = Ken Plummer | author-link = Ken Plummer (sociologist) | title = Modern Homosexualities: Fragments of Lesbian and Gay Experiences | publisher = ] | year = 2002 | pages = 187–191 | access-date = August 24, 2013|isbn =978-1-134-92242-0 | url=https://books.google.com/books?id=OSO3q4XEfz4C&pg=PA189|quote=ome sexual practices are regarded as inherently better (normal, natural, more satisfying) than others, with vaginal intercourse privileged as the 'Real Thing.' Such beliefs, influenced by views about sex as ultimately a reproductive function, continue to be perpetuated through discourses on sex despite a number of important contradictions.}}</ref>

Over time, the meaning of rape broadened in some parts of the world to include many types of sexual penetration, including anal intercourse, fellatio, cunnilingus, and penetration of the genitals or rectum by an inanimate object.<ref name="Francoeur"/> Until 2012, the ] (FBI) still considered rape a crime solely committed by men against women. In 2012, they changed the meaning from "The carnal knowledge of a female forcibly and against her will" to "The penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim." The meaning does not change federal or state criminal codes or impact charging and prosecution on the federal, state or local level, but instead assures that rape will be more accurately reported nationwide.<ref>{{cite web |url=http://blogs.usdoj.gov/blog/archives/1801 |title=An Updated Definition of Rape (U.S. Dept of Justice, January 6, 2012) |access-date=October 30, 2014 |archive-url=https://web.archive.org/web/20120313021145/http://blogs.usdoj.gov/blog/archives/1801 |archive-date=March 13, 2012 |url-status=dead}}</ref><ref>{{cite news |url=https://www.nytimes.com/2012/01/07/us/politics/federal-crime-statistics-to-expand-rape-definition.html |title=U.S. to Expand Rape Definition in Crime Statistics|newspaper=The New York Times|date=January 6, 2012 |last1=Savage|first1=Charlie|author1-link=Charlie Savage (author)}}</ref> In some instances, penetration is not required for the act to be categorized as rape.<ref name="Book04">{{cite book |editor-last=Smith |editor-first=Merril D. |title=Encyclopedia of rape |year=2004 |publisher=Greenwood Press |location=Westport, Conn. |isbn=978-0-313-32687-5 |pages=169–170 |edition=1st}}</ref>

In most societies around the world, the concept of ] exists and is criminalized. James Roffee, a senior lecturer in criminology at ],<ref>{{cite web |url=http://monash.edu/research/explore/en/persons/james-roffee(896c15d7-6f28-4bf0-8a0f-b7d6ff1553e0).html |title=Dr James Roffee|publisher=Monash university|access-date=May 22, 2017|archive-url=https://web.archive.org/web/20170204003059/http://monash.edu/research/explore/en/persons/james-roffee%28896c15d7-6f28-4bf0-8a0f-b7d6ff1553e0%29.html|archive-date=February 4, 2017|url-status=dead}}</ref> addressed potential harm associated with familial sexual activity, such as resulting children born with deficiencies. However, the law is more concerned with protecting the rights of people who are potentially subjected to such abuse. This is why familial sexual relationships are criminalized, even if all parties are consensual. There are laws prohibiting all kinds of sexual activity between relatives, not necessarily penetrative sex. These laws refer to grandparents, parents, children, siblings, aunts and uncles. There are differences between states in terms of the severity of punishments and what they consider to be a relative, including biological parents, step-parents, adoptive parents and half-siblings.<ref>{{cite journal |doi=10.1093/hrlr/ngu023 |last=Roffee |first=J. A. |date=September 2014 |title=No Consensus on Incest? Criminalisation and Compatibility with the European Convention on Human Rights |journal=Human Rights Law Review |volume=14 |issue=3 |pages=541–572}}</ref>

Another sexual matter concerning consent is ], which is a ] involving sexual activity between human and non-human animals, or a fixation on such practice.<ref name="DSM">{{cite book |title=Diagnostic and Statistical Manual of Mental Disorders: DSM-IV | publisher = ] |location=Washington, DC |year=2000 |isbn=978-0-89042-025-6 | title-link = Diagnostic and Statistical Manual of Mental Disorders }}</ref><ref name="Milner2008">{{cite book |veditors = Laws DR, O'Donohue WT |name-list-style = amp | last = Milner | first = JS |author2=Dopke CA | title = Sexual Deviance, Second Edition: Theory, Assessment, and Treatment | publisher = ] | location = New York | year = 2008 | pages = |isbn=978-1-59385-605-2 | chapter = Paraphilia Not Otherwise Specified: Psychopathology and theory}}</ref><ref name="Seto2000">{{cite book |editor = Hersen M |editor2 = Van Hasselt VB | title = Aggression and violence: an introductory text |publisher= ] |location=Boston |year=2000 |pages= 198–213 |isbn=978-0-205-26721-7 | last = Seto| first = MC|author2=Barbaree HE | chapter = Paraphilias}}</ref> Human sexual activity with non-human animals is not outlawed in some jurisdictions, but it is illegal in others under ] laws or laws dealing with ].<ref name="Perdue">{{cite book| author =Abigail Perdue| author2 =Randall Lockwood|title=Animal Cruelty and Freedom of Speech: When Worlds Collide|publisher =]| year = 2014 | pages = 6–8| access-date = December 9, 2014 |isbn = 978-1-55753-633-4| url =https://books.google.com/books?id=R1ncAwAAQBAJ&pg=PA6}}</ref>

===Romantic relationships===
] depiction of ] and a ]]]

====Marriage and relationships====
Sexual intercourse has traditionally been considered an essential part of a marriage, with many religious customs requiring ] of the marriage and citing marriage as the most appropriate union for sexual reproduction (procreation).<!-- NOTE: This is also sourced in the bullet-point examples list below.--><ref name="Hogan">{{cite book| author =Margaret Monahan Hogan|title =Marriage as a Relationship: Real and Rational|publisher = ] | year = 2002 | page = 88 | access-date = September 1, 2015 |isbn = 978-0-87462-657-5| url =https://books.google.com/books?id=HuztAAAAMAAJ&q=Marriage+as+a+Relationship:+Real+and+Rational}}</ref> In such cases, a failure for any reason to consummate the marriage would be considered a ground for ] (which does not require a divorce process). Sexual relations between marriage partners have been a "marital right" in various societies and religions, both historically and in modern times, especially with regard to a husband's rights to his wife.<ref name="Dwyer">{{cite book| author =James G. Dwyer|title =Religious Schools V. Children's Rights|publisher = ] | year = 2001 | pages = 72–73 | access-date = August 31, 2015 |isbn = 978-0-8014-8731-6| url =https://books.google.com/books?id=QDwD4huqyysC&pg=PA72}}</ref><ref name="Green">{{cite book| author =Ronald Green|author-link=Ronald Michael Green|title =Religion and Sexual Health: Ethical, Theological, and Clinical Perspectives, Volume 1 of Theology and Medicine|publisher = ] | year = 2013 | page = 112 | access-date = August 31, 2015 |isbn = 978-94-015-7963-6| url =https://books.google.com/books?id=h2mvBQAAQBAJ&pg=PT112}}</ref><ref name="Brook">{{cite book| author =Heather Brook|title = Conjugality: Marriage and Marriage-like Relationships Before the Law|publisher = ] | year = 2015 | pages = 71–73 | access-date = August 31, 2015 |isbn = 978-1-137-48091-0| url =https://books.google.com/books?id=rP2_CQAAQBAJ&pg=PA71}}</ref> Until the late 20th century, there was usually a ] in ]s which precluded a husband from being prosecuted under the rape law for forced sex with his wife.<ref name="Steinmetz">{{cite book| author =Suzanne K. Steinmetz| author2 =Marvin B. Sussman|title = Handbook of Marriage and the Family|publisher = ] | year = 2013 | pages = 787–788 | access-date = August 31, 2014 |isbn = 978-1-4615-7151-3| url =https://books.google.com/books?id=T6XwBwAAQBAJ&pg=PA787}}</ref> Author Oshisanya, 'lai Oshitokunbo stated, "As the legal status of women has changed, the concept of a married man's or woman's marital right to sexual intercourse has become less widely held."<ref name="Oshitokunbo">{{cite book| author =Oshisanya, 'lai Oshitokunbo|title = An Almanac of Contemporary Judicial Restatements (Criminal & Quasi Criminal Law & Procedure) vol. iii: Almanac vol. iii|publisher = Almanac Foundation | year = 2015 | page = 132 | access-date = August 31, 2015 |isbn = 978-978-51200-3-5| url =https://books.google.com/books?id=fsDOBAAAQBAJ&pg=PA132}}</ref>

] (engaging in sexual intercourse with someone other than one's spouse) has been, and remains, a criminal offense in some jurisdictions.<ref name="Brundage">{{cite book| author =]|title =Law, Sex, and Christian Society in Medieval Europe|publisher = ] | year = 2009 | pages = 609–611 | access-date = August 31, 2015 |isbn = 978-0-226-07789-5| url =https://books.google.com/books?id=SiGe-Zf0nTIC&pg=PA609}}</ref><ref name="Carlan">{{cite book| author =Philip Carlan| author2 =Lisa S. Nored| author3 =Ragan A. Downey|title =An Introduction to Criminal Law|publisher = ] | year = 2011 | page = 139 | access-date = August 31, 2015 |isbn = 978-1-4496-4721-6| url =https://books.google.com/books?id=8-tPwZyNWzkC&pg=PA139}}</ref> Sexual intercourse between unmarried partners and cohabitation of an unmarried couple are also illegal in some jurisdictions.<ref name="BBC News">{{cite news|title = Can Iran 'control' its cohabiting couples?|date = December 10, 2014|access-date=August 31, 2015|work = BBC News |url=https://www.bbc.com/news/world-middle-east-30391593}}</ref><ref name="amnesty.org">{{cite web|title=Amnesty International Report 2014/15|date=2014|access-date=August 31, 2015|publisher=]|url=https://www.amnesty.org/en/countries/middle-east-and-north-africa/morocco/report-morocco/|archive-date=May 4, 2017|archive-url=https://web.archive.org/web/20170504233053/https://www.amnesty.org/en/countries/middle-east-and-north-africa/morocco/report-morocco/|url-status=dead}}</ref> Conversely, in other countries, marriage is not required, socially or legally, in order to have sexual intercourse or to procreate (for example, the majority of births are outside of marriage in countries such as Iceland, Norway, Sweden, Denmark, Bulgaria, Estonia, Slovenia, France, Belgium).<ref name="europa.eu">{{cite web|title =Share of live births outside marriage|date = March 2, 2015|access-date=August 31, 2015|publisher = ] |url=http://ec.europa.eu/eurostat/tgm/table.do?tab=table&plugin=1&language=en&pcode=tps00018}}</ref>

With regard to ]s, the refusal to engage in sexual intercourse with one's spouse may give rise to a ], which may be listed under "grounds of abandonment".<ref name=Choudhri>{{cite book| author =Choudhri, Nihara K|title =The complete guide to divorce law|publisher = ] | year = 2004 | pages = 8–9 | access-date = August 30, 2015 |isbn = 978-0-8065-2528-0| url =https://books.google.com/books?id=5cLIO2yUA4gC&pg=PA8}}</ref> Concerning ] jurisdictions, author James G. Dwyer stated that no-fault divorce laws "have made it much easier for a woman to exit a marital relationship, and wives have obtained greater control over their bodies while in a marriage" because of legislative and judicial changes regarding the concept of a marital exemption when a man rapes his wife.<ref name="Dwyer"/>

There are various legal positions regarding the meaning and legality of sexual intercourse between persons of the same sex or gender. For example, in the 2003 ] case ], it was held that female same-sex sexual relations, and same-sex sexual practices in general, did not constitute sexual intercourse, based on a 1961 entry in '']'' that categorizes sexual intercourse as coitus; and thereby an accused wife in a divorce case was found not guilty of ].<ref name="GLAD, B vs. B">{{cite web|title=Blanchflower v. Blanchflower and Mayer|publisher=] (GLAD)|date=December 31, 2003|access-date=August 9, 2013|url=http://www.glad.org/work/cases/blanchflower-v-blanchflower-and-mayer|archive-date=November 21, 2016|archive-url=https://web.archive.org/web/20161121174107/http://www.glad.org/work/cases/blanchflower-v-blanchflower-and-mayer|url-status=dead}}</ref><ref name="courts.state.nh.us">{{cite web |title=In the Matter of David G. Blanchflower and Sian E. Blanchflower |website=New Hampshire Judicial Branch |date=November 7, 2003 |access-date=September 3, 2023 |url=http://www.courts.state.nh.us/supreme/opinions/2003/blanc150.htm |url-status=dead |archive-url=https://web.archive.org/web/20040212230629/http://www.courts.state.nh.us/supreme/opinions/2003/blanc150.htm |archive-date=February 12, 2004}}{{cbignore}}</ref> Some countries consider same-sex sexual behavior an offense punishable by imprisonment or execution; this is the case, for example, ], including ].<ref>]. Sexual Politics in Modern Iran. (2009) ]. {{ISBN|0-521-89846-3}}</ref><ref name="amnesty.org2">{{cite web|title=PUBLIC AI Index: MDE 13/010/2008. UA 17/08 Fear of imminent execution/ flogging|publisher=]|access-date=December 22, 2013|url=http://www2.amnesty.se/uaonnet.nsf/dfab8d7f58eec102c1257011006466e1/fd0b99f84da0da71c12573d7003a87a5?OpenDocument&Click=|url-status=dead|archive-url=https://web.archive.org/web/20160305004923/http://www2.amnesty.se/uaonnet.nsf/dfab8d7f58eec102c1257011006466e1/fd0b99f84da0da71c12573d7003a87a5?OpenDocument&Click=|archive-date=March 5, 2016}}</ref>

Opposition to ] is largely based on the belief that sexual intercourse and sexual orientation should be of a heterosexual nature.<ref name="Cahn and Carbone">{{Cite book|author1=Naomi R. Cahn |author2=June Carbone |title = Red families v. blue families: legal polarization and the creation of culture | publisher = ] US| year = 2010 |page =129| isbn = 978-0-19-537217-5|access-date=July 29, 2011|url=https://books.google.com/books?id=F6eeGny49J4C&pg=PA129}}</ref><ref name="Cantor">{{Cite book| author =Donald J. Cantor|title =Same-sex marriage: the legal and psychological evolution in America| publisher = ]| year = 2006 |pages =1–191| isbn = 978-0-8195-6812-0|access-date=July 29, 2011|url=https://books.google.com/books?id=lydHmmrHB8QC}}</ref><ref name="psychological">{{cite web|title=Resolution on Sexual Orientation and Marriage |author=] |year=2004| access-date=September 1, 2015 |url=http://www.apa.org/pi/families/resources/task-force/military-deployment.pdf}}</ref> The recognition of such marriages is a ], political, social, moral and religious issue in many nations, and the conflicts arise over whether same-sex couples should be allowed to enter into marriage, be required to use a different status (such as a ], which either grant equal rights as marriage or limited rights in comparison to marriage), or not have any such rights. A related issue is whether the word ''marriage'' should be applied.<ref name="Cantor"/><ref name="psychological"/>

====Religious views====
{{See also|Religion and sexuality}}
There are wide differences in religious views with regard to sexual intercourse in or outside of marriage:
* Most denominations of ], including ], have strict views or rules on what sexual practices are and are not acceptable.<ref name="Akin">{{Cite book|author=Daniel L. Akin|author-link=Daniel L. Akin| title = God on Sex: The Creator's Ideas About Love, Intimacy, and Marriage| year = 2003| publisher = ] |pages= 1–291 | isbn = 978-0-8054-2596-3|url=https://books.google.com/books?id=dInbMZK18soC|access-date=October 21, 2015}}</ref> Most Christian views on sexual intercourse are influenced by various interpretations of the ].<ref name="Hollinger">{{cite book| author =Dennis P. Hollinger|author-link=Dennis Hollinger|title =The Meaning of Sex: Christian Ethics and the Moral Life|publisher = ] | year = 2009 | pages = 30–33 | access-date = December 9, 2014 |isbn = 978-0-8010-3571-5| url =https://books.google.com/books?id=86tzBQAAQBAJ&pg=PA30}}</ref> Sexual intercourse outside of marriage, for example, is considered a ] in some churches; in such cases, sexual intercourse may be called a sacred covenant, holy, or a holy sacrament between husband and wife.<ref name="Akin"/><ref name="Hollinger"/> Historically, Christian teachings often promoted ],<ref name="Denton">{{cite book| author =Chad Denton|title =The War on Sex: Western Repression from the Torah to Victoria|publisher = ] | year = 2014 | pages = 107–117 | access-date = December 9, 2014 |isbn = 978-0-547-20488-8| url =https://books.google.com/books?id=Cl6QBQAAQBAJ&pg=PA107}}</ref> although today usually only certain members (for example, certain ]) of some groups take a vow of celibacy, forsaking both marriage and any type of sexual or romantic activity.<ref name="Hollinger"/> The Bible may be interpreted as endorsing penile-vaginal penetration as the only form of acceptable sexual activity,<ref name="Kamitsuka">{{cite book| author =Margaret D. Kamitsuka|title =The Embrace of Eros: Bodies, Desires, and Sexuality in Christianity|publisher = ] | year = 2010 | pages = 16–17 | access-date = December 9, 2014 |isbn = 978-1-4514-1351-9| url =https://books.google.com/books?id=VhIrHceA7ssC&pg=PA16}}</ref><ref name="Knauss">{{cite book| author =Stefanie Knauss|title =More Than a Provocation: Sexuality, Media and Theology|publisher = ] | year = 2014 | page = 69 | access-date = December 9, 2014 |isbn = 978-3-525-60450-2| url =https://books.google.com/books?id=mv9NAwAAQBAJ&pg=PA69}}</ref> while other interpretations view the Bible as not being clear on oral sex or other particular sexual behaviors and that it is a personal decision as to whether oral sex is acceptable within marriage.<ref name="Kamitsuka"/><ref name="Barnes">{{cite book| author =Robert G. Barnes| author2 =Rosemary J. Barnes|title=Great Sexpectations: Finding Lasting Intimacy in Your Marriage |publisher = ] | year = 1996 | page = | access-date = December 9, 2014 |isbn = 978-0-310-20137-3| url =https://archive.org/details/greatsexpectatio0000barn| url-access =registration}}</ref><ref name="Scheepers">{{cite book| author =Christo Scheepers|publisher = Struik Christian Media|title=Between the Covers: Sexual freedom through the bond of marriage | year = 2012 | page = 53 | access-date = December 9, 2014 |isbn = 978-1-4153-2056-3| url =https://books.google.com/books?id=LJzpAwAAQBAJ&pg=PT53}}</ref> Some sects consider the use of birth control to prevent sexual reproduction a grave sin against God and marriage, as they believe that the main purpose of marriage, or one of its primary purposes, is to produce children, while other sects do not hold such beliefs.<ref name="Oliphant">{{cite book| author =Jill Oliphant|title =OCR Religious Ethics for AS and A2|publisher = ] | year = 2010 | page = 213 | access-date = September 1, 2015 |isbn = 978-1-136-99291-9| url=https://books.google.com/books?id=VmJd87byr1AC&pg=PT213}}</ref>
** In the Roman Catholic Church, if a matrimonial celebration takes place (ratification), but the spouses have not yet engaged in intercourse (consummation), then the marriage is considered to be a marriage via '']''. Such a marriage, regardless of the reason for non-consummation, can be dissolved by the ].<ref name="d'Avray">{{cite book| author =D. L. d'Avray|title =Rationalities in History: A Weberian Essay in Comparison|publisher = ] | year = 2010 | pages = –178 | access-date = September 1, 2015 |isbn = 978-1-139-49050-4| url =https://archive.org/details/rationalitie_dav_2010_000_10426673| url-access =registration}}</ref>
** In ] (LDS Church) sexual relations within the bonds of matrimony are seen as sacred. Latter-day Saints consider sexual relations to be ordained of God for the creation of children and for the expression of love between husband and wife. Members are discouraged from having any sexual relations before marriage, and from being unfaithful to their spouses after marriage.<ref name="Swatos">{{cite book| author =William H. Swatos| author2 =Peter Kivisto|title=Encyclopedia of Religion and Society|publisher =]| year = 1998 | page = 464 | access-date = December 9, 2014 |isbn = 978-0-7619-8956-1| url =https://books.google.com/books?id=6TMFoMFe-D8C&pg=PA464}}</ref>
** ] believe that sexual intercourse is the root of all sin and that all people should therefore be celibate, including married couples. The original Shaker community that peaked at 6,000 full members in 1840 dwindled to ].<ref>{{cite news |title=The Last Ones Standing |author=Chase, Stacey |date=July 23, 2006 |newspaper=] |url=http://www.boston.com/news/globe/magazine/articles/2006/07/23/the_last_ones_standing/?page=full |archive-url=https://web.archive.org/web/20060813114148/https://www.boston.com/news/globe/magazine/articles/2006/07/23/the_last_ones_standing/?page=full |archive-date=August 13, 2006 |url-status=dead |access-date=July 26, 2023}}</ref>
* In ], a married Jewish man is required to provide his wife with sexual pleasure called ''onah'' (literally, "her time"), which is one of the conditions he takes upon himself as part of the Jewish marriage contract, '']'', that he gives her during the Jewish wedding ceremony. In ], sexual desire is not evil, but must be satisfied in the proper time, place and manner.<ref name="Zilney">{{cite book| author =Laura J. Zilney| author2 =Lisa Anne Zilney|title=Perverts and Predators: The Making of Sexual Offending Laws|publisher =]| year = 2009 | pages = –8| access-date = December 9, 2014 |isbn = 978-0-7425-6624-8| url =https://archive.org/details/pervertspredator0000ziln| url-access =registration}}</ref>
* ] views sex within marriage as something pleasurable, a spiritual activity, and a duty.<ref name=columbia/><ref name=islam>Abdul Rahman bin Abdul Karim al-Sheha. Islamic Perspective of Sex (2003) Saudi Arabia. {{ISBN|9960-43-140-1}}</ref><ref name=islam2>Fatima M. D'Oyen. The Miracle of Life. (2007) Islamic Foundation (UK). {{ISBN|0-86037-355-X}}</ref> In Shia Islam, men are allowed to marry upto four wives at a time with whom they can engage in sexual activities, including intercourse.<ref>{{Cite web |date=2015-07-15 |title=Polygamy |url=https://allaboutshias.com/polygamy-2/ |access-date=2024-09-07 |website=All About Shias |language=en-US}}</ref> Shia women are allowed to enter only one marriage at a time, whether temporary or permanent.
* ] has varied views about sexuality,<ref name="columbia">Don S. Browning, Martha Christian Green, John Witte. Sex, marriage, and family in world religions. (2006) Columbia University Press. {{ISBN|0-231-13116-X}} </ref> but according to the ], ''sex'' is considered as a normal activity that is necessary for a fulfilling and happy life.<ref>{{Cite journal |last=Sharma |first=Arvind |author-link=Arvind Sharma |date=1999 |title=The Puruṣārthas: An Axiological Exploration of Hinduism |url=https://www.jstor.org/stable/40018229 |journal=The Journal of Religious Ethics |volume=27 |issue=2 |pages=223–256 |doi=10.1111/0384-9694.00016 |jstor=40018229 |issn=0384-9694}}</ref>
* ] ethics, in its most general formulation, holds that one should neither be attached to nor crave sensual pleasure since it binds one to the cycle of birth and death, ], and prevents one attaining the goal of ]. Since Buddhist monastics (i.e. ]s and ]s) are to be fully dedicated towards this goal, they undertake the training rule of total abstinence from sexual intercourse, i.e. of celibacy. Other monastic training rules from the Code of Discipline (] or Pratimoksasutra) and canonical ] scriptures are to prevent masturbation, lustfully touching and speaking to members of the other sex, and other forms of sexual behaviour. Buddhist lay people undertake the ], the third of which is avoiding sexual misconduct. ] says that this precept "relates primarily to the avoidance of causing suffering by one's sexual behaviour. Adultery—'going with the wife of another'—is the most straightforward breach of this precept. The wrongness of this is seen as partly in terms of its being an expression of greed, and partly in terms of its harm to others. It is said that a man breaks the precept if he has intercourse with women who are engaged, or who are still protected by any relative, or young girls not protected by a relative, Clearly, rape and incest are breaches of the precept."<ref>]. ''An Introduction to Buddhist Ethics: Foundations, Values and Issues''. Cambridge, 2000: 71-72.</ref> The Buddhist Canonical scriptures contain no other regulations or recommendations for lay people—for example, with regards homosexuality, masturbation, sexual practices and contraceptives. However, in keeping with the Buddhist ethical principles of not-harming and avoiding shame, guilt and remorse, socially taboo forms of sexuality as well as obsessive sexual activities can also be seen as being included in the third precept. Later Buddhist authors such as ] give various clarifications and recommendations.<ref>]. ''An Introduction to Buddhist Ethics: Foundations, Values and Issues''. Cambridge, 2000: 71-74.</ref>
* In the ], sexual relationships are permitted only between a husband and wife.<ref>Kenneth E. Bowers. God Speaks Again: An Introduction to the Baháʼí Faith. (2004) Baháʼí Publishing. {{ISBN|1-931847-12-6}}</ref>
* ]s, with an emphasis on strong interpersonal ethics, do not place boundaries on the occurrence of sexual intercourse among consenting adults.<ref>] and ]. A Chosen Faith: An Introduction to Unitarian Universalism. (1998) Beacon Press. {{ISBN|0-8070-1617-9}}</ref>
* According to the ] and ] religion, the power of ] is the root of all evil and worse than murder.<ref name="Liz_Hodgkinson_Peace">{{cite book | last = Hodgkinson | first = Liz | author-link = Liz Hodgkinson | title = Peace and Purity: The Story of the Brahma Kumaris a Spiritual Revolution | year = 2002 | publisher = HCI | isbn = 978-1-55874-962-7 | pages = 2–29}}</ref> Purity (celibacy) is promoted for peace and to prepare for life in forthcoming Heaven on earth for 2,500 years when children will be created by the power of the mind.<ref>Babb, Lawrence A. (1987). ''Redemptive Encounters: Three Modern Styles in the Hindu Tradition'' (Comparative Studies in Religion and Society). Oxford University Press. {{ISBN|0-7069-2563-7}}. "Sexual intercourse is unnecessary for reproduction because the souls that enter the world during the first half of the Cycle are in possession of a special yogic power (yog bal) by which they conceive children."</ref><ref>] (2001). The New Believers. Cassell & Co. pp. 265. {{ISBN|0-304-35592-5}}.</ref>
* ]ns are told, as declared within the ], to "''et worship be within the heart that rejoiceth; for behold, all acts of love and pleasure are rituals.''" This statement appears to allow one freedom to explore sensuality and pleasure, and mixed with the final maxim within the ]—"''26. Eight words the Wiccan Rede fulfill—an' it harm none, do what ye will.''"<ref>]; ''Wiccan-Pagan Potpourri''; Green Egg, №69; Ostara 1974</ref>—Wiccans are encouraged to be responsible with their sexual encounters, in whatever variety they may occur.<ref>]. The Truth about Witchcraft (1971) Doubleday. page 128. {{ISBN|0-09-004860-1}}</ref>
* ] maintained that "In the beginning of married life the partners are drawn to each other by lust as well as love; but with conscious and deliberate cooperation they can gradually lessen the element of lust and increase the element of love. Through this process of sublimation, lust ultimately gives place to deep love."<ref>] (1995). ''Discourses''. Myrtle Beach: Sheriar Press. p. 109. {{ISBN|978-1-880619-09-4}}.</ref>

In some cases, the sexual intercourse between two people is seen as contrary to religious law or doctrine. In many religious communities, including the ] and ], religious leaders are expected to refrain from sexual intercourse in order to devote their full attention, energy, and loyalty to their religious duties.<ref>{{ill|William Skudlarek|de}}. Demythologizing Celibacy: Practical Wisdom from Christian and Buddhist Monasticism. (2008) Liturgical Press. {{ISBN|0-8146-2947-4}}</ref>

==Other animals==
{{Main|Copulation (zoology)|Animal sexual behaviour}}
{{See also|Sexual coercion among animals}}
] in the ], ]]]
]]]
In ], ''copulation'' often means the process in which a male introduces sperm into the female's body, especially directly into her reproductive tract.<ref name="Kent"/><ref name="Copulation1"/> ]s have separate male and female sexes. Before mating and copulation, the male spider spins a small web and ejaculates on it. He then stores the sperm in reservoirs on his large ]s, from which he transfers sperm to the female's genitals. The females can store sperm indefinitely.<ref name="RFB2004Spiders">{{cite book | author=Ruppert, E.E. | author2=Fox, R.S. | author3=Barnes, R.D. | name-list-style=amp | title=Invertebrate Zoology | publisher=Brooks/Cole | edition=7th | isbn=978-0-03-025982-1 | year=2004 | pages= | chapter=Chelicerata: Araneae | url=https://archive.org/details/isbn_9780030259821/page/571 }}</ref>

Many animals that live in water use ], whereas ] may have developed from a need to maintain ]s in a liquid medium in the ] epoch. Internal fertilization with many vertebrates (such as ]s, some ], and most ]s) occur via ]l copulation (see also ]), while ]s copulate vaginally, and many ] ]s reproduce sexually with external fertilization.<ref name="Starr">{{cite book| author =Cecie Starr| author2 =Christine Evers| author3 =Lisa Starr|title=Cengage Advantage Books: Biology: A Human Emphasis|publisher =]| year = 2010 | pages = 630–631| access-date = December 9, 2010 |isbn =978-1-133-17005-1| url =https://books.google.com/books?id=DdU8AAAAQBAJ&pg=PA631}}</ref><ref name="Denecke">{{cite book| author =Edward J. Denecke Jr.|title=New York State Grade 8 Intermediate Level Science Test|publisher =]| year = 2006 | page = 105| access-date = December 9, 2014 |isbn = 978-0-7641-3433-3| url =https://books.google.com/books?id=dbF6g4geyfsC&pg=PA105}}</ref>

For primitive ]s, the male deposits ] on the substrate, sometimes stored within a special structure; ] involves inducing the female to take up the sperm package into her genital opening, but there is no actual copulation.<ref name="Yadav">{{cite book| author =M. Yadav|title=Breeding in Insects|publisher =Discovery Publishing House| year = 2003 | page = 59| access-date = December 9, 2014 |isbn = 978-81-7141-737-7| url =https://books.google.com/books?id=ZC5obBYtusEC&pg=PA59}}</ref><ref name="Engelmann">{{cite book| author =Franz Engelmann|title=The Physiology of Insect Reproduction: International Series of Monographs in Pure and Applied Biology: Zoology|publisher =]| year = 2013 | pages = 58–59| access-date = December 9, 2014 |isbn = 978-1-4831-8653-5| url =https://books.google.com/books?id=4bXYBAAAQBAJ&pg=PA58}}</ref> In groups that have reproduction similar to spiders, such as ], males extrude sperm into secondary copulatory structures removed from their genital opening, which are then used to inseminate the female. In dragonflies, it is a set of modified ] on the second abdominal segment.<ref name="Leonard">{{cite book| author =Janet Leonard| author2 =Alex Cordoba-Aguilar|title=The Evolution of Primary Sexual Characters in Animals|publisher =]| year = 2010 | page =334| access-date = December 9, 2014 |isbn = 978-0-19-971703-3| url =https://books.google.com/books?id=PgtXj5R6OfMC&pg=PA334}}</ref> In advanced groups of insects, the male uses its ], a structure formed from the terminal segments of the abdomen, to deposit sperm directly (though sometimes in a capsule called a '']'') into the female's reproductive tract.<ref name="Gullan">{{cite book| author =P. J. Gullan| author2 =P. S. Cranston|title=The Insects: An Outline of Entomology|publisher =]| year = 2009| page = 124| access-date = December 9, 2014 |isbn = 978-1-4051-4457-5| url =https://books.google.com/books?id=E_6-pGOLUgcC&pg=PA124}}</ref>

Bonobos, chimpanzees and dolphins are species known to engage in heterosexual behaviors even when the female is not in estrus, which is a point in her reproductive cycle suitable for successful impregnation. These species are also known to ].<ref name="Non-human"/> In these animals, the use of sexual intercourse has evolved beyond reproduction to apparently serve additional social functions (such as bonding).<ref name="Balcombe"/>


==See also== ==See also==
{{Portal|Human sexuality}}
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==References== ==References==
{{Reflist|2}} {{Reflist|30em}}

==External links== ==External links==
{{commons|Sexual intercourse in humans|Sexual intercourse}} {{commons|Sexual intercourse in humans|Sexual intercourse}}
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* Janssen, D. F.,
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Latest revision as of 00:34, 3 January 2025

Penetrative sexual activity for reproduction or sexual pleasure This article is primarily about humans. For other animals, see Animal sexual behaviour. For other uses, see Sex (disambiguation). "Copulation" redirects here. For copulation among other animals, see Copulation (zoology). For the biological functions of sexual intercourse, see Penile-vaginal intercourse.

Sexual intercourse in the missionary position depicted by Édouard-Henri Avril (1892)

Sexual intercourse (also coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the male penis inside the female vagina for sexual pleasure, reproduction, or both. This is also known as vaginal intercourse or vaginal sex. Sexual penetration has been known by humans since the dawn of time, and has been an instinctive form of sexual behaviour and psychology among humans. Other forms of penetrative sexual intercourse include anal sex (penetration of the anus by the penis), oral sex (penetration of the mouth by the penis or oral penetration of the female genitalia), fingering (sexual penetration by the fingers) and penetration by use of a dildo (especially a strap-on dildo), and vibrators. These activities involve physical intimacy between two or more people and are usually used among humans solely for physical or emotional pleasure. They can contribute to human bonding.

There are different views on what constitutes sexual intercourse or other sexual activity, which can impact on views of sexual health. Although sexual intercourse, particularly the term coitus, generally denotes penile–vaginal penetration and the possibility of creating offspring, it also commonly denotes penetrative oral sex and penile–anal sex, especially the latter. It usually encompasses sexual penetration, while non-penetrative sex has been labeled outercourse, but non-penetrative sex may also be considered sexual intercourse. Sex, often a shorthand for sexual intercourse, can mean any form of sexual activity. Because people can be at risk of contracting sexually transmitted infections during these activities, safer sex practices are recommended by health professionals to reduce transmission risk.

Various jurisdictions place restrictions on certain sexual acts, such as adultery, incest, sexual activity with minors, prostitution, rape, zoophilia, sodomy, premarital sex and extramarital sex. Religious beliefs also play a role in personal decisions about sexual intercourse or other sexual activity, such as decisions about virginity, or legal and public policy matters. Religious views on sexuality vary significantly between different religions and sects of the same religion, though there are common themes, such as prohibition of adultery.

Reproductive sexual intercourse between non-human animals is more often called copulation, and sperm may be introduced into the female's reproductive tract in non-vaginal ways among the animals, such as by cloacal copulation. For most non-human mammals, mating and copulation occur at the point of estrus (the most fertile period of time in the female's reproductive cycle), which increases the chances of successful impregnation. However, bonobos, dolphins and chimpanzees are known to engage in sexual intercourse regardless of whether the female is in estrus, and to engage in sex acts with same-sex partners. Like humans engaging in sexual activity primarily for pleasure, this behavior in these animals is also presumed to be for pleasure, and a contributing factor to strengthening their social bonds.

Behaviors

See also: Human sexual activity and Human sexuality

Definitions

Modern artwork of a couple engaged in vaginal intercourse
19th-century erotic interpretation of Roman emperor Hadrian and Antinous engaged in anal intercourse, by Édouard-Henri Avril

Sexual intercourse may be called coitus, copulation, coition, or intercourse. Coitus is derived from the Latin word coitio or coire, meaning "a coming together or joining together" or "to go together", and is known under different ancient Latin names for a variety of sexual activities, but usually denotes penile–vaginal penetration. This is often called vaginal intercourse or vaginal sex. Vaginal sex, and less often vaginal intercourse, may also denote any vaginal sexual activity, particularly if penetrative, including sexual activity between lesbian couples. Copulation, by contrast, more often denotes the mating process, especially for non-human animals; it can mean a variety of sexual activities between opposite-sex or same-sex pairings, but generally means the sexually reproductive act of transferring sperm from a male to a female or sexual procreation between a man and a woman.

Although sex and having sex also most commonly denote penile–vaginal intercourse, sex can be significantly broad in its meaning and may cover any penetrative or non-penetrative sexual activity between two or more people. The World Health Organization (WHO) states that non-English languages and cultures use different words for sexual activity, "with slightly different meanings". Various vulgarisms, slang, and euphemisms are used for sexual intercourse or other sexual activity, such as fuck, screw, shag, and the phrase "sleep together". The laws of some countries use the euphemism, carnal knowledge. Penetration of the vagina by the erect penis is additionally known as intromission, or by the Latin name immissio penis (Latin for "insertion of the penis"). The age of first sexual intercourse is called sexarche.

Vaginal, anal and oral sex are recognized as sexual intercourse more often than other sexual behaviors. Sexual activity that does not involve penile-vaginal sex or other sexual penetration might be used to retain virginity (sometimes called technical virginity) or labeled outercourse. One reason virginity loss is often based on penile–vaginal intercourse is because heterosexual couples may engage in anal or oral sex as a way of being sexually active while maintaining that they are virgins since they have not engaged in the reproductive act of coitus. Some gay men consider frot or oral sex as a way of maintaining their virginities, with penile-anal penetration used as sexual intercourse and for virginity loss, while other gay men may consider frot or oral sex as their main forms of sexual activity. Lesbians may categorize oral sex or fingering as sexual intercourse and subsequently an act of virginity loss, or tribadism as a primary form of sexual activity.

Researchers commonly use sexual intercourse to denote penile–vaginal intercourse while using specific words, such as anal sex or oral sex, for other sexual behaviors. Scholars Richard M. Lerner and Laurence Steinberg state that researchers also "rarely disclose" how they conceptualize sex "or even whether they resolved potential discrepancies" in conceptualizations of sex. Lerner and Steinberg attribute researchers' focus on penile–vaginal sex to "the larger culture's preoccupation with this form of sexual activity", and have expressed concern that the "widespread, unquestioned equation of penile–vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question matches what the researcher had in mind'". This focus can also relegate other forms of mutual sexual activity to foreplay or contribute to them not being regarded as "real sex", and limits the meaning of rape. It may also be that conceptually conflating sexual activity with vaginal intercourse and sexual function hinders and limits information about sexual behavior that non-heterosexual people may be engaging in, or information about heterosexuals who may be engaging in non–vaginal sexual activity.

Studies regarding the meaning of sexual intercourse sometimes come into conflict. While most consider penile–vaginal intercourse to be sex, whether anal or oral intercourse are considered sex is more debatable, with oral sex ranking lowest. The Centers for Disease Control and Prevention (CDC) stated that "although there are only limited national data about how often adolescents engage in oral sex, some data suggest that many adolescents who engage in oral sex do not consider it to be 'sex'; therefore they may use oral sex as an option to experience sex while still, in their minds, remaining abstinent". Upton et al. stated, "It is possible that individuals who engage in oral sex, but do not consider it as 'sex', may not associate the acts with the potential health risks they can bring." In other cases, condom use is a factor, with some men stating that sexual activity involving the protection of a condom is not "real sex" or "the real thing". This view is common among men in Africa, where sexual activity involving the protection of a condom is often associated with emasculation because condoms prevent direct penile–to–skin genital contact.

Stimulation

Sexual intercourse or other sexual activity can encompass various sexually stimulating factors (physiological stimulation or psychological stimulation), including different sex positions (such as the missionary position, the most common human sex position) or the use of sex toys. Foreplay may precede some sexual activities, often leading to sexual arousal of the partners and resulting in the erection of the penis or natural lubrication of the vagina. It is also common for people to be as sexually satisfied by being kissed, touched erotically, or held as they are during sexual intercourse.

Non-primate females copulate only when in estrus, but sexual intercourse is possible at any time of the menstrual cycle for women. Sex pheromones facilitate copulatory reflexes in various organisms, but, in humans, the detection of pheromones is impaired and they have only residual effects. Non-primate females put themselves in the crucial lordosis position and remain motionless, but these motor copulatory reflexes are no longer functional in women.

Édouard-Henri Avril depiction of a woman on top position, a position that is more likely to stimulate the clitoris

During coitus, the partners orient their hips to allow the penis to move back and forth in the vagina to cause friction, typically without fully removing the penis. In this way, they stimulate themselves and each other, often continuing until orgasm in either or both partners is achieved.

For human females, stimulation of the clitoris plays a significant role in sexual activity; 70–80% of women require direct clitoral stimulation to achieve orgasm, though indirect clitoral stimulation (for example, via vaginal intercourse) may also be sufficient (see orgasm in females). Because of this, some couples may engage in the woman on top position or the coital alignment technique, a technique combining the "riding high" variation of the missionary position with pressure-counterpressure movements performed by each partner in rhythm with sexual penetration, to maximize clitoral stimulation.

Édouard-Henri Avril depiction of cunnilingus in the life of Sappho

Anal sex involves stimulation of the anus, anal cavity, sphincter valve or rectum; it most commonly means the insertion of a man's penis into another person's rectum, but may also mean the use of sex toys or fingers to penetrate the anus, or oral sex on the anus (anilingus), or pegging.

Oral sex consists of all the sexual activities that involve the use of the mouth and throat to stimulate genitalia or anus. It is sometimes performed to the exclusion of all other forms of sexual activity, and may include the ingestion or absorption of semen (during fellatio) or vaginal fluids (during cunnilingus).

Fingering involves the digital manipulation of the clitoris, rest of the vulva, vagina or anus for the purpose of sexual arousal and sexual stimulation; it may constitute the entire sexual encounter or it may be part of mutual masturbation, foreplay or other sexual activities.

Reproduction

Main articles: Sexual reproduction and Human reproduction
Chance of fertilization by menstrual cycle day relative to ovulation
"Coition of a Hemisected Man and Woman" (c. 1492), an interpretation of what happens inside the body during coitus, by Leonardo da Vinci

Natural human reproduction involves penile–vaginal penetration, during which semen, containing male gametes known as sperm cells or spermatozoa, is ejaculated through the penis into the vagina. The sperm passes through the vaginal vault, cervix and into the uterus, and then into the fallopian tubes. Millions of sperm are ejaculated to increase the chances of fertilization (see sperm competition), but only one is sufficient to fertilize an egg or ovum. When a fertile ovum from the female is present in the fallopian tubes, the male gamete fertilizes the ovum, forming a new embryo. Pregnancy begins after the fertilized ovum is implanted in the lining of the uterus (the endometrium).

Pregnancy rates for sexual intercourse are highest during the menstrual cycle time from some five days before until approximately one day after ovulation (this is sometimes called the fertile window). For optimal pregnancy chance, there are recommendations of vaginal intercourse every one or two days, or every two or three days. Some people who are trying to conceive may choose to time vaginal intercourse with the fertile window, a practice that is sometimes called 'timed intercourse'. Timed intercourse using urine tests that predict ovulation may help improve the rate of pregnancy and live births for some couples trying to conceive such as those who have been trying for less than 12 months and who are under 40 years old; however, it is not clear from medical evidence if timed intercourse improves the rate of ultrasound-confirmed pregnancies and it is also not clear if timed intercourse has an effect on a person's level of stress or their quality of life. Studies have shown no significant difference between different sex positions and pregnancy rate, as long as it results in ejaculation into the vagina.

When a sperm donor has sexual intercourse with a woman who is not his partner and for the sole purpose of impregnating the woman, this may be known as natural insemination, as opposed to artificial insemination. Artificial insemination is a form of assisted reproductive technology, which are methods used to achieve pregnancy by artificial or partially artificial means. For artificial insemination, sperm donors may donate their sperm through a sperm bank, and the insemination is performed with the express intention of attempting to impregnate the female; to this extent, its purpose is the medical equivalent of sexual intercourse. Intracervical insemination (ICI), which involves the deposit of (usually) raw semen in the vagina of a woman, is in effect a substitute for intercourse and is often contrasted with 'normal intercourse' in this context. Reproductive methods also extend to gay and lesbian couples. For gay male pairings, there is the option of surrogate pregnancy; for lesbian couples, there is donor insemination in addition to choosing surrogate pregnancy. Some women use artificial insemination to become single mothers by choice.

Safe sex and birth control

See also: Comparison of birth control methods

There are a variety of safe sex methods that are practiced by heterosexual and same-sex couples, including non-penetrative sex acts, and heterosexual couples may use oral or anal sex (or both) as a means of birth control. However, pregnancy can still occur with anal sex or other forms of sexual activity if the penis is near the vagina (such as during intercrural sex or other genital-genital rubbing) and its sperm is deposited near the vagina's entrance and travels along the vagina's lubricating fluids; the risk of pregnancy can also occur without the penis being near the vagina because sperm may be transported to the vaginal opening by the vagina coming in contact with fingers or other non-genital body parts that have come in contact with semen.

Safe sex is a relevant harm reduction philosophy and condoms are used as a form of safe sex and contraception. Condoms are widely recommended for the prevention of sexually transmitted infections (STIs). According to reports by the National Institutes of Health (NIH) and World Health Organization (WHO), correct and consistent use of latex condoms reduces the risk of HIV/AIDS transmission by approximately 85–99% relative to risk when unprotected. Condoms are rarely used for oral sex and there is significantly less research on behaviors with regard to condom use for anal and oral sex. The most effective way to avoid sexually transmitted infections is to abstain from sexual intercourse, especially vaginal, anal, and oral sexual intercourse.

Decisions and options concerning birth control can be affected by cultural reasons, such as religion, gender roles or folklore. In the predominantly Catholic countries Ireland, Italy, and the Philippines, fertility awareness and the rhythm method are emphasized while disapproval is expressed with regard to other contraceptive methods. Worldwide, sterilization is a more common birth control method, and use of the intrauterine device (IUD) is the most common and effective way of reversible contraception. Conception and contraception are additionally a life-and-death situation in developing countries, where one in three women give birth before age 20; however, 90% of unsafe abortions in these countries could be prevented by effective contraception use.

The National Survey of Sexual Health and Behavior (NSSHB) indicated in 2010 that "1 of 4 acts of vaginal intercourse are condom-protected in the U.S. (1 in 3 among singles)," that "condom use is higher among black and Hispanic Americans than among white Americans and those from other racial groups," and that "adults using a condom for intercourse were just as likely to rate the sexual extent positively in terms of arousal, pleasure and orgasm than when having intercourse without one".

Prevalence

Penile–vaginal penetration is the most common form of sexual intercourse. Studies indicate that most heterosexual couples engage in vaginal intercourse nearly every sexual encounter. The National Survey of Sexual Health and Behavior (NSSHB) reported in 2010 that vaginal intercourse is "the most prevalent sexual behavior among men and women of all ages and ethnicities". Clint E. Bruess et al. stated that it "is the most frequently studied behavior" and is "often the focus of sexuality education programming for youth." Weiten et al. said that it "is the most widely endorsed and practiced sexual act in our society."

Regarding oral or anal intercourse, the CDC stated in 2009, "Studies indicate that oral sex is commonly practiced by sexually active male-female and same-gender couples of various ages, including adolescents." Oral sex is significantly more common than anal sex. The 2010 NSSHB study reported that vaginal intercourse was practiced more than insertive anal intercourse among men, but that 13% to 15% of men aged 25 to 49 practiced insertive anal intercourse. Receptive anal intercourse was infrequent among men, with approximately 7% of men aged 14 to 94 years old having said that they were a receptive partner during anal intercourse. The study said that fewer women reported engaging in anal sex than other partnered sexual behaviors. It was estimated that 10% to 14% of women aged 18 to 39 years old practiced anal sex in the past 90 days, and that most of the women who engage in anal sex said they practiced it once a month or a few times a year.

Age at first intercourse

The prevalence of sexual intercourse has been compared cross-culturally. In 2003, Michael Bozon of the French Institut national d'études démographiques conducted a cross-cultural study titled "At what age do women and men have their first sexual intercourse?" In the first group of the contemporary cultures he studied, which included sub-Saharan Africa (listing Mali, Senegal and Ethiopia), the data indicated that the age of men at sexual initiation in these societies is at later ages than that of women, but is often extra-marital; the study considered the Indian subcontinent to also fall into this group, though data was only available from Nepal. In the second group, the data indicated families encouraged daughters to delay marriage, and to abstain from sexual activity before that time. However, sons are encouraged to gain experience with older women or prostitutes before marriage. Age of men at sexual initiation in these societies is at lower ages than that of women; this group includes south European and Latin cultures (Portugal, Greece and Romania are noted) and such from Latin America (Brazil, Chile, and the Dominican Republic). The study considered many Asian societies to also fall into this group, although matching data was only available from Thailand. In the third group, age of men and women at sexual initiation was more closely matched; there were two sub-groups, however. In non-Latin, Catholic countries (Poland and Lithuania are mentioned), age at sexual initiation was higher, suggesting later marriage and reciprocal valuing of male and female virginity. The same pattern of late marriage and reciprocal valuing of virginity was reflected in Singapore and Sri Lanka. The study considered China and Vietnam to also fall into this group, though data were not available. In northern and eastern European countries, age at sexual initiation was lower, with both men and women involved in sexual intercourse before any union formation; the study listed Switzerland, Germany and the Czech Republic as members of this group.

Concerning United States data, tabulations by the National Center for Health Statistics report that the age of first sexual intercourse was 17.1 years for both males and females in 2010. The CDC stated that 45.5 percent of girls and 45.7 percent of boys had engaged in sexual activity by 19 in 2002; in 2011, reporting their research from 2006 to 2010, they stated that 43% of American unmarried teenage girls and 42% of American unmarried teenage boys have ever engaged in sexual intercourse. The CDC also reports that American girls will most likely lose their virginity to a boy who is 1 to 3 years older than they are. Between 1988 and 2002, the percentage of people in the U.S. who had sexual intercourse between the ages of 15 and 19 fell from 60 to 46 percent for never-married males, and from 51 to 46 percent for never-married females.

Health effects

Benefits

In humans, sexual intercourse and sexual activity in general have been reported as having health benefits as varied as increased immunity by increasing the body's production of antibodies and subsequent lower blood pressure, and decreased risk of prostate cancer. Sexual intimacy and orgasms increase levels of the hormone oxytocin (also known as "the love hormone"), which can help people bond and build trust. Oxytocin is believed to have a more significant impact on women than on men, which may be why women associate sexual attraction or sexual activity with romance and love more than men do. A long-term study of 3,500 people between ages 18 and 102 by clinical neuropsychologist David Weeks indicated that, based on impartial ratings of the subjects' photographs, sex on a regular basis is associated with people looking significantly chronologically younger. However this does not imply causality.

Vaginal intercourse for the first time increases vaginal immune activity.

Risks

Sexually transmitted infections (STIs) are bacteria, viruses or parasites that are spread by sexual contact, especially vaginal, anal, or oral intercourse, or unprotected sex. Oral sex is less risky than vaginal or anal intercourse. Many times, STIs initially do not cause symptoms, increasing the risk of unknowingly passing the infection on to a sex partner or others.

There are 19 million new cases of sexually transmitted infections every year in the U.S., and, in 2005, the World Health Organization (WHO) estimated that 448 million people aged 15–49 were infected per year with curable STIs (such as syphilis, gonorrhea and chlamydia). Some STIs can cause a genital ulcer; even if they do not, they increase the risk of both acquiring and passing on HIV up to ten-fold. Hepatitis B can also be transmitted through sexual contact. Globally, there are about 257 million chronic carriers of hepatitis B. HIV is one of the world's leading infectious killers; in 2010, approximately 30 million people were estimated to have died because of it since the beginning of the epidemic. Of the 2.7 million new HIV infections estimated to occur worldwide in 2010, 1.9 million (70%) were in Africa. The World Health Organization also stated that the "estimated 1.2 million Africans who died of HIV-related illnesses in 2010 comprised 69% of the global total of 1.8 million deaths attributable to the epidemic." It is diagnosed by blood tests, and while no cure has been found, it can be controlled by management through antiretroviral drugs for the disease, and patients can enjoy healthy and productive lives.

In cases where infection is suspected, early medical intervention is highly beneficial in all cases. The CDC stated "the risk of HIV transmission from an infected partner through oral sex is much less than the risk of HIV transmission from anal or vaginal sex," but that "measuring the exact risk of HIV transmission as a result of oral sex is very difficult" and that this is "because most sexually active individuals practice oral sex in addition to other forms of sex, such as vaginal or anal sex, when transmission occurs, it is difficult to determine whether it occurred as a result of oral sex or other more risky sexual activities". They added that "several co-factors may increase the risk of HIV transmission through oral sex"; this includes ulcers, bleeding gums, genital sores, and the presence of other STIs.

In 2005, the World Health Organization estimated that 123 million women become pregnant worldwide each year, and around 87 million of those pregnancies or 70.7% are unintentional. Approximately 46 million pregnancies per year reportedly end in induced abortion. Approximately 6 million U.S. women become pregnant per year. Out of known pregnancies, two-thirds result in live births and roughly 25% in abortions; the remainder end in miscarriage. However, many more women become pregnant and miscarry without even realizing it, instead mistaking the miscarriage for an unusually heavy menstruation. The U.S. teenage pregnancy rate fell by 27 percent between 1990 and 2000, from 116.3 pregnancies per 1,000 girls aged 15–19 to 84.5. This data includes live births, abortions, and fetal losses. Almost 1 million American teenage women, 10% of all women aged 15–19 and 19% of those who report having had intercourse, become pregnant each year.

Sexual activity can increase the expression of a gene transcription factor called ΔFosB (delta FosB) in the brain's reward center; consequently excessively frequent engagement in sexual activity on a regular (daily) basis can lead to the overexpression of ΔFosB, inducing an addiction to sexual activity. Sexual addiction or hypersexuality is often considered an impulse control disorder or a behavioral addiction. It has been linked to atypical levels of dopamine, a neurotransmitter. This behavior is characterized by a fixation on sexual intercourse and disinhibition. It was proposed that this 'addictive behavior' be classified in DSM-5 as an impulsive–compulsive behavioral disorder. Addiction to sexual intercourse is thought to be genetically linked. Those having an addiction to sexual intercourse have a higher response to visual sexual cues in the brain. Those seeking treatment will typically see a physician for pharmacological management and therapy. One form of hypersexuality is Kleine–Levin syndrome. It is manifested by hypersomnia and hypersexuality and remains relatively rare.

Sexual activity can directly cause death, particularly due to coronary circulation complications, which is sometimes called coital death, coital sudden death or coital coronary. However, coital deaths are significantly rare. People, especially those who get little or no physical exercise, have a slightly increased risk of triggering a heart attack or sudden cardiac death when they engage in sexual intercourse or any vigorous physical exercise that is engaged in on a sporadic basis. Regular exercise reduces, but does not eliminate, the increased risk.

Duration and genital complications

See also: Intravaginal ejaculation latency time and Coitus reservatus

Sexual intercourse, when involving a male participant, often ends when the male has ejaculated, and thus the partner might not have time to reach orgasm. In addition, premature ejaculation (PE) is common, and women often require a substantially longer duration of stimulation with a sexual partner than men do before reaching an orgasm. Scholars, such as Weiten et al., state that "many couples are locked into the idea that orgasms should be achieved only through intercourse ," that "the word foreplay suggests that any other form of sexual stimulation is merely preparation for the 'main event'" and that "because women reach orgasm through intercourse less consistently than men," they are likelier than men to fake an orgasm to satisfy their sexual partners.

Painting of a couple (an Indian prince and lady) prolonging sexual intercourse

In 1991, scholars from the Kinsey Institute stated, "The truth is that the time between penetration and ejaculation varies not only from man to man, but from one time to the next for the same man." They added that the appropriate length for sexual intercourse is the length of time it takes for both partners to be mutually satisfied, emphasizing that Kinsey "found that 75 percent of men ejaculated within two minutes of penetration. But he didn't ask if the men or their partners considered two minutes mutually satisfying" and "more recent research reports slightly longer times for intercourse". A 2008 survey of Canadian and American sex therapists stated that the average time for heterosexual intercourse (coitus) was 7 minutes and that 1 to 2 minutes was too short, 3 to 7 minutes was adequate and 7 to 13 minutes desirable, while 10 to 30 minutes was too long.

Anorgasmia is regular difficulty reaching orgasm after ample sexual stimulation, causing personal distress. This is significantly more common in women than in men, which has been attributed to the lack of sex education with regard to women's bodies, especially in sex-negative cultures, such as clitoral stimulation usually being key for women to orgasm. The physical structure of coitus favors penile stimulation over clitoral stimulation; the location of the clitoris then usually necessitates manual or oral stimulation in order for the woman to achieve orgasm. Approximately 25% of women report difficulties with orgasm, 10% of women have never had an orgasm, and 40% or 40–50% have either complained about sexual dissatisfaction or experienced difficulty becoming sexually aroused at some point in their lives.

Vaginismus is involuntary tensing of the pelvic floor musculature, making coitus, or any form of penetration of the vagina, distressing, painful and sometimes impossible for women. It is a conditioned reflex of the pubococcygeus muscle, and is sometimes referred to as the PC muscle. Vaginismus can be hard to overcome because if a woman expects to experience pain during sexual intercourse, this can cause a muscle spasm, which results in painful sexual intercourse. Treatment of vaginismus often includes both psychological and behavioral techniques, including the use of vaginal dilators. Additionally, the use of Botox as a medical treatment for vaginismus has been tested and administered. Painful or uncomfortable sexual intercourse may also be categorized as dyspareunia.

Approximately 40% of males reportedly have some form of erectile dysfunction (ED) or impotence, at least occasionally. Premature ejaculation has been reported to be more common than erectile dysfunction, although some estimates suggest otherwise. Due to various meanings of the disorder, estimates for the prevalence of premature ejaculation vary significantly more than for erectile dysfunction. For example, the Mayo Clinic states, "Estimates vary, but as many as 1 out of 3 men may be affected by at some time." Further, "Masters and Johnson speculated that premature ejaculation is the most common sexual dysfunction, even though more men seek therapy for erectile difficulties" and that this is because "although an estimated 15 percent to 20 percent of men experience difficulty controlling rapid ejaculation, most do not consider it a problem requiring help, and many women have difficulty expressing their sexual needs". The American Urological Association (AUA) estimates that premature ejaculation could affect 21 percent of men in the United States.

For those whose impotence is caused by medical conditions, prescription drugs such as Viagra, Cialis, and Levitra are available. However, doctors caution against the unnecessary use of these drugs because they are accompanied by serious risks such as increased chance of heart attack. The selective serotonin reuptake inhibitor (SSRI) and antidepressant drug dapoxetine has been used to treat premature ejaculation. In clinical trials, those with PE who took dapoxetine experienced sexual intercourse three to four times longer before orgasm than without the drug. Another ejaculation-related disorder is delayed ejaculation, which can be caused as an unwanted side effect of antidepressant medications such as fluvoxamine; however, all SSRIs have ejaculation-delaying effects, and fluvoxamine has the least ejaculation-delaying effects.

Sexual intercourse often remains possible after major medical treatment of the reproductive organs and structures. This is especially true for women. Even after extensive gynecological surgical procedures (such as hysterectomy, oophorectomy, salpingectomy, dilation and curettage, hymenotomy, Bartholin gland surgery, abscess removal, vestibulectomy, labia minora reduction, cervical conization, surgical and radiological cancer treatments and chemotherapy), sexual intercourse can continue. Reconstructive surgery remains an option for women who have experienced benign and malignant conditions. Men and women who have underwent extensive surgery should consult their medical team to understand how their treatment or surgery affects sex and how long they should wait before having sexual intercourse after a surgery.

Disabilities and other complications

Main article: Sexuality and disability

Obstacles that those with disabilities face with regard to engaging in sexual intercourse include pain, depression, fatigue, negative body image, stiffness, functional impairment, anxiety, reduced libido, hormonal imbalance, and drug treatment or side effects. Sexual functioning has been regularly identified as a neglected area of the quality of life in patients with rheumatoid arthritis. For those that must take opioids for pain control, sexual intercourse can become more difficult. Having a stroke can also largely impact on the ability to engage in sexual intercourse. Although disability-related pain, including as a result of cancer, and mobility impairment can hamper sexual intercourse, in many cases, the most significant impediments to sexual intercourse for individuals with a disability are psychological. In particular, people who have a disability can find sexual intercourse daunting due to issues involving their self-concept as a sexual being, or a partner's discomfort or perceived discomfort. Temporary difficulties can arise with alcohol and sex, as alcohol can initially increase interest through disinhibition but decrease capacity with greater intake; however, disinhibition can vary depending on the culture.

People with mental disabilities also are subject to challenges in participating in sexual intercourse. This can include the lack of a knowledgeable healthcare provider trained and experienced in counseling those with intellectual disabilities on sexual intercourse. Those with intellectual disabilities may have hesitations regarding the discussion of the topic of sex, a lack of sexual knowledge and limited opportunities for sex education. In addition there are other barriers such as a higher prevalence of sexual abuse and assault. These crimes often remain underreported. There remains a lack of "dialogue around this population's human right to consensual sexual expression, undertreatment of menstrual disorders, and legal and systemic barriers". Women with intellectual disability may lack sexual health care and sex education. They may not recognize sexual abuse. Consensual sexual intercourse is not always an option for some. Those with intellectual disability may have limited knowledge and access to contraception, screening for sexually transmitted infections and cervical cancer.

Social effects

See also: Human mating strategies and Pair bond

Adults

Sexual intercourse may be for reproductive, relational, or recreational purposes. It often plays a strong role in human bonding. In many societies, it is normal for couples to have sexual intercourse while using some method of birth control, sharing pleasure and strengthening their emotional bond through sexual activity even though they are deliberately avoiding pregnancy.

In humans and bonobos, the female undergoes relatively concealed ovulation so that male and female partners commonly do not know whether she is fertile at any given moment. One possible reason for this distinct biological feature may be formation of strong emotional bonds between sexual partners important for social interactions and, in the case of humans, long-term partnership rather than immediate sexual reproduction.

Sexual dissatisfaction due to the lack of sexual intercourse is associated with increased risk of divorce and relationship dissolution, especially for men. Some research, however, indicates that general dissatisfaction with marriage for men results if their wives flirted with, erotically kissed or became romantically or sexually involved with another man (infidelity), and that this is especially the case for men with a lower emotional and composite marital satisfaction. Other studies report that the lack of sexual intercourse does not significantly result in divorce, though it is commonly one of the various contributors to it. According to the 2010 National Survey of Sexual Health and Behavior (NSSHB), men whose most recent sexual encounter was with a relationship partner reported greater arousal, greater pleasure, fewer problems with erectile function, orgasm, and less pain during the event than men whose last sexual encounter was with a non-relationship partner.

For women, there is often a complaint about the lack of their spouses' sexual spontaneity. Decreased sexual activity among these women may be the result of their perceived failure to maintain ideal physical attractiveness or because their sexual partners' health issues have hindered sexual intercourse. Some women express that their most satisfying sexual experiences entail being connected to someone, rather than solely basing satisfaction on orgasm. With regard to divorce, women are more likely to divorce their spouses for a one-night stand or various infidelities if they are in less cooperative or high-conflict marriages.

Research additionally indicates that non-married couples who are cohabiting engage in sexual intercourse more often than married couples, and are more likely to participate in sexual activity outside of their sexual relationships; this may be due to the "honeymoon" effect (the newness or novelty of sexual intercourse with the partner), since sexual intercourse is usually practiced less the longer a couple is married, with couples engaging in sexual intercourse or other sexual activity once or twice a week, or approximately six to seven times a month. Sexuality in older age also affects the frequency of sexual intercourse, as older people generally engage in sexual intercourse less frequently than younger people do.

Adolescents

Main article: Adolescent sexuality

Adolescents commonly use sexual intercourse for relational and recreational purposes, which may negatively or positively impact their lives. For example, while teenage pregnancy may be welcomed in some cultures, it is also commonly disparaged, and research suggests that the earlier onset of puberty for children puts pressure on children and teenagers to act like adults before they are emotionally or cognitively ready. Some studies have concluded that engaging in sexual intercourse leaves adolescents, especially girls, with higher levels of stress and depression, and that girls may be likelier to engage in sexual risk (such as sexual intercourse without the use of a condom), but it may be that further research is needed in these areas. In some countries, such as the United States, sex education and abstinence-only sex education curricula are available to educate adolescents about sexual activity; these programs are controversial, as debate exists as to whether teaching children and adolescents about sexual intercourse or other sexual activity should only be left up to parents or other caregivers.

Some studies from the 1970s through 1990s suggested an association between self-esteem and sexual intercourse among adolescents, while other studies, from the 1980s and 1990s, reported that the research generally indicates little or no relationship between self-esteem and sexual activity among adolescents. By the 1990s, the evidence mostly supported the latter, and further research has supported little or no relationship between self-esteem and sexual activity among adolescents. Scholar Lisa Arai stated, "The idea that early sexual activity and pregnancy is linked to low self-esteem became fashionable in the latter half of the 20th century, particularly in the US," adding that, "Yet, in a systematic review of the relationship between self-esteem and teenagers' sexual behaviours, attitudes and intentions (which analyzed findings from 38 publications) 62% of behavioral findings and 72% of the attitudinal findings exhibited no statistically significant associations (Goodson et al, 2006)." Studies that do find a link suggest that non-virgin boys have higher self-esteem than virgin boys and that girls who have low self-esteem and poor self-image are more prone to risk-taking behaviors, such as unprotected sex and multiple sexual partners.

Psychiatrist Lynn Ponton wrote, "All adolescents have sex lives, whether they are sexually active with others, with themselves, or seemingly not at all", and that viewing adolescent sexuality as a potentially positive experience, rather than as something inherently dangerous, may help young people develop healthier patterns and make more positive choices regarding sexual activity. Researchers state that long-term romantic relationships allow adolescents to gain the skills necessary for high-quality relationships later in life. Overall, positive romantic relationships among adolescents can result in long-term benefits. High-quality romantic relationships are associated with higher commitment in early adulthood, and are positively associated with social competence.

Ethical, religious, and legal views

General

See also: Sexual ethics, Religion and sexuality, and Sex and the law
Erotic painting on ancient Greek kylix

While sexual intercourse, as coitus, is the natural mode of reproduction for the human species, humans have intricate moral and ethical guidelines which regulate the practice of sexual intercourse and vary according to religious and governmental laws. Some governments and religions also have strict designations of what they consider appropriate and inappropriate sexual behavior, which include restrictions on the types of sex acts which are permissible. A historically prohibited or regulated sex act is anal sex.

Sexual offenses

Sexual intercourse with a person against their will, or without their consent, is rape, but may also be called sexual assault; it is considered a serious crime in most countries. More than 90% of rape victims are female, 99% of rapists male, and only about 5% of rapists are strangers to the victims.

Most countries have age of consent laws which set the minimum legal age with whom an older person may engage in sexual intercourse, usually set at 16 to 18, but ranges from 12 to 20, years of age. In some societies, an age of consent is set by non-statutory custom or tradition. Sex with a person under the age of consent, regardless of their stated consent, is often considered sexual assault or statutory rape depending on differences in ages of the participants. Some countries treat any sex with a person of diminished or insufficient mental capacity to give consent, regardless of age, as rape.

Max Slevogt depiction of rape

Robert Francoeur et al. stated that "prior to the 1970s, rape definitions of sex often included only penile-vaginal sexual intercourse." Authors Pamela J. Kalbfleisch and Michael J. Cody stated that this made it so that if "sex means penile-vaginal intercourse, then rape means forced penile-vaginal intercourse, and other sexual behaviors – such as fondling a person's genitals without her or his consent, forced oral sex, and same-sex coercion – are not considered rape"; they stated that "although some other forms of forced sexual contact are included within the legal category of sodomy (e.g., anal penetration and oral-genital contact), many unwanted sexual contacts have no legal grounding as rape in some states". Ken Plumber argued that the legal meaning "of rape in most countries is unlawful sexual intercourse which means the penis must penetrate the vagina" and that "other forms of sexual violence towards women such as forced oral sex or anal intercourse, or the insertion of other objects into the vagina, constitute the 'less serious' crime of sexual assault".

Over time, the meaning of rape broadened in some parts of the world to include many types of sexual penetration, including anal intercourse, fellatio, cunnilingus, and penetration of the genitals or rectum by an inanimate object. Until 2012, the Federal Bureau of Investigation (FBI) still considered rape a crime solely committed by men against women. In 2012, they changed the meaning from "The carnal knowledge of a female forcibly and against her will" to "The penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim." The meaning does not change federal or state criminal codes or impact charging and prosecution on the federal, state or local level, but instead assures that rape will be more accurately reported nationwide. In some instances, penetration is not required for the act to be categorized as rape.

In most societies around the world, the concept of incest exists and is criminalized. James Roffee, a senior lecturer in criminology at Monash University, addressed potential harm associated with familial sexual activity, such as resulting children born with deficiencies. However, the law is more concerned with protecting the rights of people who are potentially subjected to such abuse. This is why familial sexual relationships are criminalized, even if all parties are consensual. There are laws prohibiting all kinds of sexual activity between relatives, not necessarily penetrative sex. These laws refer to grandparents, parents, children, siblings, aunts and uncles. There are differences between states in terms of the severity of punishments and what they consider to be a relative, including biological parents, step-parents, adoptive parents and half-siblings.

Another sexual matter concerning consent is zoophilia, which is a paraphilia involving sexual activity between human and non-human animals, or a fixation on such practice. Human sexual activity with non-human animals is not outlawed in some jurisdictions, but it is illegal in others under animal abuse laws or laws dealing with crimes against nature.

Romantic relationships

Lawrence Alma-Tadema depiction of courtship and a marriage proposal

Marriage and relationships

Sexual intercourse has traditionally been considered an essential part of a marriage, with many religious customs requiring consummation of the marriage and citing marriage as the most appropriate union for sexual reproduction (procreation). In such cases, a failure for any reason to consummate the marriage would be considered a ground for annulment (which does not require a divorce process). Sexual relations between marriage partners have been a "marital right" in various societies and religions, both historically and in modern times, especially with regard to a husband's rights to his wife. Until the late 20th century, there was usually a marital exemption in rape laws which precluded a husband from being prosecuted under the rape law for forced sex with his wife. Author Oshisanya, 'lai Oshitokunbo stated, "As the legal status of women has changed, the concept of a married man's or woman's marital right to sexual intercourse has become less widely held."

Adultery (engaging in sexual intercourse with someone other than one's spouse) has been, and remains, a criminal offense in some jurisdictions. Sexual intercourse between unmarried partners and cohabitation of an unmarried couple are also illegal in some jurisdictions. Conversely, in other countries, marriage is not required, socially or legally, in order to have sexual intercourse or to procreate (for example, the majority of births are outside of marriage in countries such as Iceland, Norway, Sweden, Denmark, Bulgaria, Estonia, Slovenia, France, Belgium).

With regard to divorce laws, the refusal to engage in sexual intercourse with one's spouse may give rise to a grounds for divorce, which may be listed under "grounds of abandonment". Concerning no-fault divorce jurisdictions, author James G. Dwyer stated that no-fault divorce laws "have made it much easier for a woman to exit a marital relationship, and wives have obtained greater control over their bodies while in a marriage" because of legislative and judicial changes regarding the concept of a marital exemption when a man rapes his wife.

There are various legal positions regarding the meaning and legality of sexual intercourse between persons of the same sex or gender. For example, in the 2003 New Hampshire Supreme Court case Blanchflower v. Blanchflower, it was held that female same-sex sexual relations, and same-sex sexual practices in general, did not constitute sexual intercourse, based on a 1961 entry in Webster's Third New International Dictionary that categorizes sexual intercourse as coitus; and thereby an accused wife in a divorce case was found not guilty of adultery. Some countries consider same-sex sexual behavior an offense punishable by imprisonment or execution; this is the case, for example, in Islamic countries, including LGBT issues in Iran.

Opposition to same-sex marriage is largely based on the belief that sexual intercourse and sexual orientation should be of a heterosexual nature. The recognition of such marriages is a civil rights, political, social, moral and religious issue in many nations, and the conflicts arise over whether same-sex couples should be allowed to enter into marriage, be required to use a different status (such as a civil union, which either grant equal rights as marriage or limited rights in comparison to marriage), or not have any such rights. A related issue is whether the word marriage should be applied.

Religious views

See also: Religion and sexuality

There are wide differences in religious views with regard to sexual intercourse in or outside of marriage:

  • Most denominations of Christianity, including Catholicism, have strict views or rules on what sexual practices are and are not acceptable. Most Christian views on sexual intercourse are influenced by various interpretations of the Bible. Sexual intercourse outside of marriage, for example, is considered a sin in some churches; in such cases, sexual intercourse may be called a sacred covenant, holy, or a holy sacrament between husband and wife. Historically, Christian teachings often promoted celibacy, although today usually only certain members (for example, certain religious leaders) of some groups take a vow of celibacy, forsaking both marriage and any type of sexual or romantic activity. The Bible may be interpreted as endorsing penile-vaginal penetration as the only form of acceptable sexual activity, while other interpretations view the Bible as not being clear on oral sex or other particular sexual behaviors and that it is a personal decision as to whether oral sex is acceptable within marriage. Some sects consider the use of birth control to prevent sexual reproduction a grave sin against God and marriage, as they believe that the main purpose of marriage, or one of its primary purposes, is to produce children, while other sects do not hold such beliefs.
    • In the Roman Catholic Church, if a matrimonial celebration takes place (ratification), but the spouses have not yet engaged in intercourse (consummation), then the marriage is considered to be a marriage via ratum sed non consummatum. Such a marriage, regardless of the reason for non-consummation, can be dissolved by the pope.
    • In the Church of Jesus Christ of Latter-day Saints (LDS Church) sexual relations within the bonds of matrimony are seen as sacred. Latter-day Saints consider sexual relations to be ordained of God for the creation of children and for the expression of love between husband and wife. Members are discouraged from having any sexual relations before marriage, and from being unfaithful to their spouses after marriage.
    • Shakers believe that sexual intercourse is the root of all sin and that all people should therefore be celibate, including married couples. The original Shaker community that peaked at 6,000 full members in 1840 dwindled to three members by 2009.
  • In Judaism, a married Jewish man is required to provide his wife with sexual pleasure called onah (literally, "her time"), which is one of the conditions he takes upon himself as part of the Jewish marriage contract, ketubah, that he gives her during the Jewish wedding ceremony. In Jewish views on marriage, sexual desire is not evil, but must be satisfied in the proper time, place and manner.
  • Islam views sex within marriage as something pleasurable, a spiritual activity, and a duty. In Shia Islam, men are allowed to marry upto four wives at a time with whom they can engage in sexual activities, including intercourse. Shia women are allowed to enter only one marriage at a time, whether temporary or permanent.
  • Hinduism has varied views about sexuality, but according to the Kama Sutra, sex is considered as a normal activity that is necessary for a fulfilling and happy life.
  • Buddhist ethics, in its most general formulation, holds that one should neither be attached to nor crave sensual pleasure since it binds one to the cycle of birth and death, samsara, and prevents one attaining the goal of Nirvana. Since Buddhist monastics (i.e. bhikshus and bhikshunis) are to be fully dedicated towards this goal, they undertake the training rule of total abstinence from sexual intercourse, i.e. of celibacy. Other monastic training rules from the Code of Discipline (Patimokkha or Pratimoksasutra) and canonical Vinaya scriptures are to prevent masturbation, lustfully touching and speaking to members of the other sex, and other forms of sexual behaviour. Buddhist lay people undertake the Five Precepts, the third of which is avoiding sexual misconduct. Peter Harvey says that this precept "relates primarily to the avoidance of causing suffering by one's sexual behaviour. Adultery—'going with the wife of another'—is the most straightforward breach of this precept. The wrongness of this is seen as partly in terms of its being an expression of greed, and partly in terms of its harm to others. It is said that a man breaks the precept if he has intercourse with women who are engaged, or who are still protected by any relative, or young girls not protected by a relative, Clearly, rape and incest are breaches of the precept." The Buddhist Canonical scriptures contain no other regulations or recommendations for lay people—for example, with regards homosexuality, masturbation, sexual practices and contraceptives. However, in keeping with the Buddhist ethical principles of not-harming and avoiding shame, guilt and remorse, socially taboo forms of sexuality as well as obsessive sexual activities can also be seen as being included in the third precept. Later Buddhist authors such as Nagarjuna give various clarifications and recommendations.
  • In the Baháʼí Faith, sexual relationships are permitted only between a husband and wife.
  • Unitarian Universalists, with an emphasis on strong interpersonal ethics, do not place boundaries on the occurrence of sexual intercourse among consenting adults.
  • According to the Brahma Kumaris and Prajapita Brahma Kumaris religion, the power of lust is the root of all evil and worse than murder. Purity (celibacy) is promoted for peace and to prepare for life in forthcoming Heaven on earth for 2,500 years when children will be created by the power of the mind.
  • Wiccans are told, as declared within the Charge of the Goddess, to "et worship be within the heart that rejoiceth; for behold, all acts of love and pleasure are rituals." This statement appears to allow one freedom to explore sensuality and pleasure, and mixed with the final maxim within the Wiccan Rede—"26. Eight words the Wiccan Rede fulfill—an' it harm none, do what ye will."—Wiccans are encouraged to be responsible with their sexual encounters, in whatever variety they may occur.
  • Meher Baba maintained that "In the beginning of married life the partners are drawn to each other by lust as well as love; but with conscious and deliberate cooperation they can gradually lessen the element of lust and increase the element of love. Through this process of sublimation, lust ultimately gives place to deep love."

In some cases, the sexual intercourse between two people is seen as contrary to religious law or doctrine. In many religious communities, including the Catholic Church and Mahayana Buddhists, religious leaders are expected to refrain from sexual intercourse in order to devote their full attention, energy, and loyalty to their religious duties.

Other animals

Main articles: Copulation (zoology) and Animal sexual behaviour See also: Sexual coercion among animals
A pair of lions copulating in the Maasai Mara, Kenya
Mating houseflies

In zoology, copulation often means the process in which a male introduces sperm into the female's body, especially directly into her reproductive tract. Spiders have separate male and female sexes. Before mating and copulation, the male spider spins a small web and ejaculates on it. He then stores the sperm in reservoirs on his large pedipalps, from which he transfers sperm to the female's genitals. The females can store sperm indefinitely.

Many animals that live in water use external fertilization, whereas internal fertilization may have developed from a need to maintain gametes in a liquid medium in the Late Ordovician epoch. Internal fertilization with many vertebrates (such as reptiles, some fish, and most birds) occur via cloacal copulation (see also hemipenis), while mammals copulate vaginally, and many basal vertebrates reproduce sexually with external fertilization.

For primitive insects, the male deposits spermatozoa on the substrate, sometimes stored within a special structure; courtship involves inducing the female to take up the sperm package into her genital opening, but there is no actual copulation. In groups that have reproduction similar to spiders, such as dragonflies, males extrude sperm into secondary copulatory structures removed from their genital opening, which are then used to inseminate the female. In dragonflies, it is a set of modified sternites on the second abdominal segment. In advanced groups of insects, the male uses its aedeagus, a structure formed from the terminal segments of the abdomen, to deposit sperm directly (though sometimes in a capsule called a spermatophore) into the female's reproductive tract.

Bonobos, chimpanzees and dolphins are species known to engage in heterosexual behaviors even when the female is not in estrus, which is a point in her reproductive cycle suitable for successful impregnation. These species are also known to engage in same-sex sexual behaviors. In these animals, the use of sexual intercourse has evolved beyond reproduction to apparently serve additional social functions (such as bonding).

See also

References

  1. ^ Sexual intercourse most commonly means penile–vaginal penetration for sexual pleasure or sexual reproduction; dictionary sources state that it especially means this, and scholarly sources over the years agree. See, for example;
    • "Sexual intercourse". Dictionary.com. Retrieved August 24, 2024.
    • "Sexual intercourse". Merriam-Webster. Retrieved August 24, 2024.
    • Richard M. Lerner; Laurence Steinberg (2004). Handbook of Adolescent Psychology. John Wiley & Sons. pp. 193–196. ISBN 978-0-471-69044-3. Retrieved April 29, 2013. When researchers use the term sex, they nearly always mean sexual intercourse – more specifically, penile–vaginal intercourse. The widespread, unquestioned equation of penile–vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question matches what the researcher had in mind.'
    • Fedwa Malti-Douglas (2007). Encyclopedia of Sex and Gender: A-C. Macmillan Reference. p. 308. ISBN 978-0-02-865961-9. Sexual intercourse. he term coitus indicates a specific act of sexual intercourse that also is known as coition or copulation. This 'coming together' is generally understood in heteronormative terms as the penetration of a woman's vagina by a man's penis.
    • Irving B. Weiner; W. Edward Craighead (2010). The Corsini Encyclopedia of Psychology. Vol. 4. John Wiley & Sons. p. 1577. ISBN 978-0-470-17023-6. Retrieved August 21, 2013. Human sexual intercourse, or coitus, is one of the most common sexual outlets among adults. Sexual intercourse generally refers to penile penetration of the vagina.
    • Clint E. Bruess; Elizabeth Schroeder (2013). Sexuality Education Theory and Practice. Jones & Bartlett Publishers. p. 152. ISBN 978-1-4496-4928-9. Retrieved December 5, 2014. In many cultures around the world, vaginal sex is what is usually implied when people refer to 'having sex' or 'sexual intercourse.' It is the most frequently studied behavior and is often the focus of sexuality education programming for youth.
    • Cecie Starr; Beverly McMillan (2015). Human Biology. Cengage Learning. p. 339. ISBN 978-1-305-44594-9. Retrieved December 27, 2017. Coitus and copulation are both technical terms for sexual intercourse. The male sex act involves an erection, in which the limp penis stiffens and lengthens. It also involves ejaculation, the forceful expulsion of semen into the urethra and out from the penis. During coitus, pelvic thrusts stimulate the penis as well as the female's clitoris and vaginal wall. The stimulation triggers rhythmic, involuntary contractions in smooth muscle in the male reproductive tract, especially the vas deferens and the prostate. The contractions rapidly force sperm out of each epididymis. They also force the contents of seminal vesicles and the prostate gland into the urethra. The resulting mixture, semen, is ejaculated into the vagina.
    • Janell L. Carroll (2018). Sexuality Now: Embracing Diversity. Cengage Learning. p. 289. ISBN 978-1-337-67206-1. Retrieved November 22, 2019. Vaginal intercourse (also referred to as sexual intercourse) involves inserting the penis into the vagina.
  2. ^ Alters S (2012). Essential Concepts for Healthy Living. Jones & Bartlett Publishers. pp. 180–181. ISBN 978-1-4496-3062-1. Most heterosexuals are familiar with the notion of 'having sex' or sexual intercourse as vaginal sex, the insertion of a penis into a vagina. Vaginal sex, or coitus, is the most common and popular form of intimate sexual activity between partners.
  3. Carroll JL (2018). Sexuality Now: Embracing Diversity. Cengage Learning. p. 289. ISBN 978-1-337-67206-1. Vaginal intercourse (also referred to as sexual intercourse) involves inserting the penis into the vagina.
  4. ^ "Sexual Intercourse". Discovery Health. Archived from the original on August 22, 2008. Retrieved January 12, 2008.
  5. Rathus SA, Nevid JS, Rathus LF (2010). Human Sexuality in a World of Diversity. Allyn & Bacon. p. 251. ISBN 978-0-205-78606-0.
  6. ^ Freberg L (2009). Discovering Biological Psychology. Cengage Learning. pp. 308–310. ISBN 978-0-547-17779-3.
  7. ^ "Defining sexual health: Report of a technical consultation on sexual health" (PDF). World Health Organization. January 2002. p. 4. Archived from the original (PDF) on September 6, 2012. Retrieved September 5, 2012. In English, the term 'sex' is often used to mean 'sexual activity' and can cover a range of behaviours. Other languages and cultures use different terms, with slightly different meanings.
  8. * "Sexual Intercourse". Discovery.com. Archived from the original on August 22, 2008. Retrieved January 12, 2008.
    • Nancy W. Denney; David Quadagno (2008). Human Sexuality. Mosby-Year Book. p. 273. ISBN 978-0-8016-6374-1. Although the term intercourse is usually used to refer to the insertion of the penis into the vagina, it is also used to refer to oral intercourse or anal intercourse in which the penis is inserted into the mouth or the anus, respectively.
  9. ^ Kahn AP, Fawcett J (2008). The Encyclopedia of Mental Health. Infobase Publishing. p. 111. ISBN 978-0-8160-6454-0.
  10. ^ Hales D (2008). An Invitation to Health Brief 2010–2011. Cengage Learning. pp. 269–271. ISBN 978-0-495-39192-0.
  11. ^ Kumar B, Gupta S (2014). Sexually Transmitted Infections. Elsevier Health Sciences. p. 93. ISBN 978-81-312-2978-1.
  12. ^ See page 11 onwards and pages 47–49 for views on what constitutes virginity loss and therefore sexual intercourse or other sexual activity; source discusses how gay and lesbian individuals define virginity loss, and how the majority of researchers and heterosexuals define virginity loss/"technical virginity" by whether a person has engaged in penile–vaginal sex. Carpenter LM (2005). Virginity Lost: An Intimate Portrait of First Sexual Experiences. NYU Press. pp. 295 pages. ISBN 978-0-8147-1652-6.
  13. Strong B, DeVault C, Cohen TF (2010). The Marriage and Family Experience: Intimate Relationship in a Changing Society. Cengage Learning. p. 186. ISBN 978-0-534-62425-5. Retrieved October 8, 2011. Most people agree that we maintain virginity as long as we refrain from sexual (vaginal) intercourse. But occasionally we hear people speak of 'technical virginity' Data indicate that 'a very significant proportion of teens ha had experience with oral sex, even if they haven't had sexual intercourse, and may think of themselves as virgins' Other research, especially research looking into virginity loss, reports that 35% of virgins, defined as people who have never engaged in vaginal intercourse, have nonetheless engaged in one or more other forms of heterosexual sexual activity (e.g., oral sex, anal sex, or mutual masturbation).
  14. ^ Michael Kent (2000). Advanced biology. Oxford University Press. pp. 250–253. ISBN 978-0-19-914195-1. Retrieved October 21, 2015.
  15. Showick Thorpe; Edgar Thorpe (2009). The Pearson General Studies Manual 2009, 1/e. Pearson Education India. p. 1.79. ISBN 978-81-317-2133-9. Retrieved October 21, 2015.
  16. ^
  17. ^ Balcombe, Jonathan (2006). Pleasurable Kingdom: Animals and the Nature of Feeling Good. Palgrave Macmillan. pp. 106–118. ISBN 978-0-230-55227-2.
  18. ^ See page 302 for orgasm information, and pages 285–286 for definitions, prevalence and length of sexual intercourse. Carroll JL (2012). Discovery Series: Human Sexuality (1st ed.). Cengage Learning. pp. 656 pages. ISBN 978-1-111-84189-8.
  19. Milkman HB, Wanberg KW (2004). Pathways to Self-Discovery and Change: Criminal Conduct and Substance Abuse Treatment for Adolescents. SAGE. pp. 254–255. ISBN 978-1-4129-0614-2.
  20. ^ Kinetics H (2009). Health and Wellness for Life. Human Kinetics. p. 207. ISBN 978-0-7360-6850-5.
  21. ^ Barrows EM (2011). Animal Behavior Desk Reference: A Dictionary of Animal Behavior, Ecology, and Evolution. Taylor & Francis. pp. 122–124. ISBN 978-1-4398-3651-4.
  22. ^ "Copulation". Dorland's Medical Dictionary for Health Consumers, 2007/TheFreeDictionary.com for various dictionary definitions. Retrieved September 6, 2012.
  23. "Copulation". The American Heritage Dictionary of the English Language, Fifth Edition. 2011. Retrieved August 23, 2013.
  24. "Fuck". Merriam-Webster. Retrieved March 30, 2013.
  25. "Shag". Merriam-Webster. Retrieved March 30, 2013.
  26. "Sleep together". TheFreeDictionary.com. Retrieved March 30, 2013.
  27. "Intromission". Merriam-Webster. Retrieved December 26, 2012.
  28. "sexarche - oi". Concise Medical Dictionary. Oxford University Press. Archived from the original on June 24, 2019. Retrieved July 4, 2017.
  29. Lara LS, Abdo CH (2016). "Age at Time of Initial Sexual Intercourse and Health of Adolescent Girls". Journal of Pediatric and Adolescent Gynecology. 29 (5): 417–423. doi:10.1016/j.jpag.2015.11.012. ISSN 1083-3188. PMID 26655691.
  30. Gross MJ (2003). "Like a Virgin". The Advocate. Here Media. pp. 44–45. 0001-8996. Retrieved March 13, 2011.
  31. Dolby T (February 2004). "Why Some Gay Men Don't Go All The Way". Out. Here. pp. 76–77. Retrieved February 12, 2011.
  32. ^ Lerner RM, Steinberg L (2004). Handbook of Adolescent Psychology. John Wiley & Sons. pp. 193–196. ISBN 978-0-471-69044-3. When researchers use the term sex, they nearly always mean sexual intercourse – more specifically, penile–vaginal intercourse... The widespread, unquestioned equation of penile–vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question matches what the researcher had in mind.'
  33. Greenberg JS, Bruess CE, Conklin SC (2007). Exploring the Dimensions of Human Sexuality. Jones & Bartlett Learning. p. 429. ISBN 978-0-7637-4148-8. 9780763741488.
  34. ^ Weiten W, Dunn DS, Hammer EY (2016). Psychology Applied to Modern Life: Adjustment in the 21st Century. Cengage Learning. p. 349. ISBN 978-0-7637-4148-8. 1305968476. Retrieved December 27, 2017.
  35. ^ McClelland SI (2012). "Measuring Sexual Quality of Life: Ten Recommendations for Health Psychologists". In Baum A, Revenson TA, Singer J (eds.). Handbook of Health Psychology (2nd ed.). Psychology Press. pp. 259–260. ISBN 978-0-8058-6461-8. Retrieved April 30, 2013.
  36. ^ Kalbfleisch PJ, Cody MJ (2012). Gender Power and Communication in Human Relationships. Routledge. p. 153. ISBN 978-1-136-48050-8. Retrieved April 30, 2013.
  37. ^ UD, TK (2014). Promoting Healthy Behaviour: A Practical Guide. Routledge. pp. 243–248. ISBN 978-1-317-81887-8.
  38. ^ Aggleton P, Ball A, Mane P (2013). Sex, Drugs and Young People: International Perspectives. Routledge. pp. 74–75. ISBN 978-1-134-33310-3.
  39. ^ "Oral Sex and HIV Risk" (PDF). Centers for Disease Control and Prevention (CDC). June 2009. Archived from the original (PDF) on May 10, 2013. Retrieved August 30, 2013.
  40. ^ Jonathan Engel (2009). The Epidemic: A History of Aids. HarperCollins. p. 242. ISBN 978-0-06-185676-1. Retrieved August 30, 2013. Many men simply did not like the feel of condoms, or associated them with emasculation. They say, 'Unless it's flesh on flesh, it's not real sex...
  41. ^ Naomi N. Wekwete (2010). Adolescent Pregnancy Challenges in the Era of HIV and AIDS: A Case Study of a Selected Rural Area in Zimbabwe. African Books Collective. p. 49. ISBN 978-99944-55-48-5. Retrieved August 30, 2013.
  42. Monge-Nájera, J., Rodríguez, M., & González, M. I. (2017). Time to deconstruct the concepts of "foreplay" and "intercourse": the real structure of human sexual encounters. Cuadernos de Investigación UNED [es], 9(1), 59-64.
  43. ^ Wayne Weiten; Margaret A. Lloyd; Dana S. Dunn; Elizabeth Yost Hammer (2008). Psychology Applied to Modern Life: Adjustment in the 21st Century. Cengage Learning. pp. 422–423. ISBN 978-0-495-55339-7. Retrieved January 5, 2012. The man-above, or "missionary," position is the most common sex position.
  44. Taormino, Tristan (2009). The Big Book of Sex Toys. Quiver. p. 52. ISBN 978-1-59233-355-4. Retrieved June 9, 2014.
  45. ^ Wayne Weiten; Dana S. Dunn; Elizabeth Yost Hammer (2011). Psychology Applied to Modern Life: Adjustment in the 21st Century. Cengage Learning. pp. 384–386. ISBN 978-1-111-18663-0. Retrieved January 5, 2012.
  46. Sandra Alters; Wendy Schiff (2011). Essential Concepts for Healthy Living Update. Jones & Bartlett Publishers. p. 154. ISBN 978-1-4496-5374-3. Retrieved December 9, 2014.
  47. ^ Pfaus J.G., Flanagan-Cato L.M., Blaustein J.D. (2015) Female sexual behavior. in Plant T., Zeleznik A. (Eds). Knobil and Neill's Physiology of Reproduction. Academic Press, 4th edition
  48. ^ Harry T. Reis; Susan Sprecher (2009). Encyclopedia of Human Relationships. Vol. 1. SAGE. pp. 541–543. ISBN 978-1-4129-5846-2.
  49. Dixson A.F. (2012) Primate sexuality: Comparative studies of the Prosimians, Monkeys, Apes, and Human Beings. Oxford University Press, 2nd edition.
  50. Doty R.L. (2014) Human Pheromones: Do They Exist? in Mucignat-Caretta C. (Ed). Neurobiology of Chemical Communication. Boca Raton (FL): CRC Press, (19).
  51. ^ Keath Roberts (2006). Sex. Lotus Press. p. 145. ISBN 978-81-89093-59-4. Retrieved August 17, 2012.
  52. Cecie Starr; Beverly McMillan (2008). Human Biology. Cengage Learning. p. 314. ISBN 978-0-495-56181-1. Retrieved April 30, 2013.
  53. Joseph A. Flaherty; John Marcell Davis; Philip G. Janicak (1993). Psychiatry: Diagnosis & therapy. A Lange clinical manual. Appleton & Lange (Original from Northwestern University). pp. 544 pages. ISBN 978-0-8385-1267-8. The amount of time of sexual arousal needed to reach orgasm is variable — and usually much longer — in women than in men; thus, only 20–30% of women attain a coital climax. b. Many women (70–80%) require manual clitoral stimulation...
  54. Mah K, Binik YM (January 7, 2001). "The nature of human orgasm: a critical review of major trends". Clinical Psychology Review. 21 (6): 823–856. doi:10.1016/S0272-7358(00)00069-6. PMID 11497209. Women rated clitoral stimulation as at least somewhat more important than vaginal stimulation in achieving orgasm; only about 20% indicated that they did not require additional clitoral stimulation during intercourse.
  55. Kammerer-Doak D, Rogers RG (June 2008). "Female Sexual Function and Dysfunction". Obstetrics and Gynecology Clinics of North America. 35 (2): 169–183. doi:10.1016/j.ogc.2008.03.006. PMID 18486835. Most women report the inability to achieve orgasm with vaginal intercourse and require direct clitoral stimulation ... About 20% have coital climaxes...
  56. Lloyd, Elisabeth Anne (2005). The case of the female orgasm: bias in the science of evolution. Harvard University Press. p. 53. ISBN 978-0-674-01706-1. OCLC 432675780. Retrieved January 5, 2012.
  57. O'Connell HE, Sanjeevan KV, Hutson JM (October 2005). "Anatomy of the clitoris". The Journal of Urology. 174 (4 Pt 1): 1189–95. doi:10.1097/01.ju.0000173639.38898.cd. PMID 16145367. S2CID 26109805.
    Mascall, Sharon (June 11, 2006). "Time for rethink on the clitoris". BBC News.
  58. Hurlbert DF, Apt C (1995). "The coital alignment technique and directed masturbation: a comparative study on female orgasm". Journal of Sex & Marital Therapy. 21 (1): 21–29. doi:10.1080/00926239508405968. PMID 7608994.
  59. Barry R. Komisaruk; Beverly Whipple; Sara Nasserzadeh; Carlos Beyer-Flores (2009). The Orgasm Answer Guide. JHU Press. pp. 108–109. ISBN 978-0-8018-9396-4. Retrieved November 6, 2011.
  60. Paula Kamen (2000). Her Way: Young Women Remake the Sexual Revolution. New York University Press. pp. 74–77. ISBN 978-0-8147-4733-9. Retrieved September 5, 2012.
  61. Hite, Shere (2003). The Hite Report: A Nationwide Study of Female Sexuality. New York, NY: Seven Stories Press. pp. 512 pages. ISBN 978-1-58322-569-1. Retrieved March 2, 2012.
  62. Carroll, Janell L. (2009). Sexuality Now: Embracing Diversity. Cengage Learning. pp. 118, 252, and 264. ISBN 978-0-495-60274-3. Retrieved June 23, 2012.
  63. Dunson, D.B.; Baird, D.D.; Wilcox, A.J.; Weinberg, C.R. (1999). "Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation". Human Reproduction. 14 (7): 1835–1839. doi:10.1093/humrep/14.7.1835. ISSN 1460-2350. PMID 10402400.
  64. ^ Richard Evan Jones; Kristin H. López (2006). Human Reproductive Biology. Academic Press. pp. 205-206. ISBN 978-0-12-088465-0. Retrieved June 5, 2022.
  65. Cecie Starr; Beverly McMillan (2015). Human Biology. Cengage Learning. p. 339. ISBN 978-1-305-44594-9. Retrieved December 27, 2017.
  66. ^ Gibbons, Tatjana; Reavey, Jane; Georgiou, Ektoras X; Becker, Christian M (September 15, 2023). Cochrane Gynaecology and Fertility Group (ed.). "Timed intercourse for couples trying to conceive". Cochrane Database of Systematic Reviews. 2023 (9): CD011345. doi:10.1002/14651858.CD011345.pub3. PMC 10501857. PMID 37709293.
  67. "How to get pregnant". Mayo Clinic. November 2, 2016. Retrieved February 16, 2018.
  68. "Fertility problems: assessment and treatment, Clinical guideline [CG156]". National Institute for Health and Care Excellence. February 20, 2013. Retrieved February 16, 2018. Published date: February 2013. Last updated: September 2017
  69. Philip B. Imler & David Wilbanks (November 2019). "The Essential Guide to Getting Pregnant" (PDF). American Pregnancy Association. Archived from the original (PDF) on June 1, 2018. Retrieved February 16, 2018.
  70. James Bobick; Naomi Balaban (2008). The Handy Anatomy Answer Book. Visible Ink Press. pp. 306–307. ISBN 978-1-57859-328-6. Retrieved August 21, 2013.
  71. R.K. Sharma (2007). Concise Textbook Of Forensic Medicine & Toxicology. Elsevier India. pp. 113–116. ISBN 978-81-312-1145-8. Retrieved October 13, 2013.
  72. Mosby, Marie T. O'Toole (2013). Mosby's Medical Dictionary. Elsevier Health Sciences. p. 138. ISBN 978-0-323-11258-1. Retrieved October 13, 2013.
  73. Berkowitz D, Marsiglio W (2007). "Gay Men: Negotiating Procreative, Father, and Family Identities". Journal of Marriage and Family. 69 (2): 366–381. doi:10.1111/j.1741-3737.2007.00371.x. S2CID 38458107.
  74. Joan M. Burda (2008). Gay, lesbian, and transgender clients: a lawyer's guide. American Bar Association. pp. 69–74. ISBN 978-1-59031-944-4. Retrieved July 28, 2011.
  75. Fiese, Barbara (2016). "Single Mothers by Choice: Mother–Child Relationships and Children's Psychological Adjustment". J Fam Psychol. 30 (4): 409–418. doi:10.1037/fam0000188. PMC 4886836. PMID 26866836.
  76. Jerry D. Durham; Felissa R. Lashley (2000). The Person With HIV/AIDS: Nursing Perspectives (3rd ed.). Springer Publishing Company. p. 103. ISBN 978-81-223-0004-8. Retrieved January 29, 2012.
  77. Robert Crooks; Karla Baur (2010). Our Sexuality. Cengage Learning. pp. 286–289. ISBN 978-0-495-81294-4. Retrieved August 30, 2012. Noncoital forms of sexual intimacy, which have been called outercourse, can be a viable form of birth control. Outercourse includes all avenues of sexual intimacy other than penile–vaginal intercourse, including kissing, touching, mutual masturbation, and oral and anal sex.
  78. Feldmann J, Middleman AB (2002). "Adolescent sexuality and sexual behavior". Current Opinion in Obstetrics and Gynecology. 14 (5): 489–493. doi:10.1097/00001703-200210000-00008. PMID 12401976. S2CID 29206790.
  79. Thomas, R. Murray (2009). Sex and the American teenager seeing through the myths and confronting the issues. Lanham, Md.: Rowman & Littlefield Education. p. 81. ISBN 978-1-60709-018-2. Retrieved October 21, 2015.
  80. Edlin, Gordon (2012). Health & Wellness. Jones & Bartlett Learning. p. 213. ISBN 978-1-4496-3647-0. Retrieved October 21, 2015.
  81. ^ Chin HB, Sipe TA, Elder R, Mercer SL, Chattopadhyay SK, Jacob V, Wethington HR, Kirby D, Elliston DB, Griffith M, Chuke SO, Briss SC, Ericksen I, Galbraith JS, Herbst JH, Johnson RL, Kraft JM, Noar SM, Romero LM, Santelli J (2012). "The Effectiveness of Group-Based Comprehensive Risk-Reduction and Abstinence Education Interventions to Prevent or Reduce the Risk of Adolescent Pregnancy, Human Immunodeficiency Virus, and Sexually Transmitted Infections". American Journal of Preventive Medicine. 42 (3): 272–294. doi:10.1016/j.amepre.2011.11.006. PMID 22341164. Archived from the original on January 2, 2020. Retrieved July 23, 2013.
  82. National Institute of Allergy and Infectious Diseases; National Institutes of Health, Department of Health and Human Services (July 20, 2001). Workshop Summary: Scientific Evidence on Condom Effectiveness for Sexually Transmitted Disease (STD) Prevention (PDF). Hyatt Dulles Airport, Herndon, Virginia. pp. 13–15. Archived from the original (PDF) on March 7, 2010. Retrieved March 20, 2009.
  83. "Effectiveness of male latex condoms in protecting against pregnancy and sexually transmitted infections". World Health Organization. 2000. Archived from the original on May 9, 2010. Retrieved July 23, 2013.
  84. Bhushan Kumar, Somesh Gupta (2014). Sexually Transmitted Infections E book. Elsevier Health Sciences. p. 122. ISBN 978-81-312-2978-1.
  85. Dianne Hales (2010). An Invitation to Health: Choosing to Change. Cengage Learning. pp. 301–302. ISBN 978-0-538-73655-8. Retrieved March 30, 2013.
  86. Winner B, Peipert JF, Zhao Q, Buckel C, Madden T, Allsworth JE, Secura GM (2012). "Effectiveness of long-acting reversible contraception". N. Engl. J. Med. 366 (21): 1998–2007. doi:10.1056/NEJMoa1110855. PMID 22621627. S2CID 16812353.
  87. "Findings from the National Survey of Sexual Health and Behavior, Centre for Sexual Health Promotion, Indiana University". The Journal of Sexual Medicine. 7 (Supplement 5): 4. 2010. Retrieved March 4, 2011.
  88. Clint E. Bruess; Elizabeth Schroeder (2013). Sexuality Education Theory and Practice. Jones & Bartlett Publishers. p. 152. ISBN 978-1-4496-4928-9. Retrieved December 5, 2014.
  89. ^ Bozon, Michael (2003). "At what age do women and men have their first sexual intercourse? World comparisons and recent trends" (PDF). Population and Societies. 391: 1–4. Archived from the original (PDF) on March 4, 2016.
  90. ^ Graziella Caselli; Guillaume Wunsch; Daniel Courgeau; Jacques Vallin (2005). Demography – Analysis and Synthesis: A Treatise in Population. Academic Press. pp. 490–501. ISBN 978-0-12-765660-1. Retrieved September 6, 2013.
  91. "Key Statistics from the National Survey of Family Growth". Centers for Disease Control and Prevention (CDC). Retrieved February 9, 2013.
  92. ^ "Teenagers in the United States: Sexual Activity, Contraceptive Use, and Childbearing, 2006–2010 National Survey of Family Growth" (PDF). Centers for Disease Control and Prevention (CDC). Retrieved December 26, 2012.
  93. "Teenagers in the United States: Sexual Activity, Contraceptive Use, and Childbearing, 2002" (PDF). Centers for Disease Control and Prevention (CDC). Retrieved February 9, 2013.
  94. ^ Andrew Steptoe; Kenneth Freedland; J. Richard Jennings; Maria M. Llabre; Stephen B Manuck; Elizabeth J. Susman (2010). Handbook of Behavioral Medicine: Methods and Applications. Springer Science & Business Media. pp. 60–61. ISBN 978-0-387-09488-5. Retrieved December 7, 2014.
  95. ^ Theresa Hornstein; Jeri Schwerin (2012). Biology of Women. Cengage Learning. p. 205. ISBN 978-1-285-40102-7. Retrieved December 7, 2014.
  96. Carol Sigelman; Elizabeth Rider (2011). Life-Span Human Development. Cengage Learning. p. 452. ISBN 978-1-111-34273-9. Retrieved December 7, 2014.
  97. Northrup, Christiane (2010). Women's Bodies, Women's Wisdom: Creating Physical and Emotional Health and Healing. Bantam. p. 232. ISBN 978-0-553-80793-6. Retrieved October 21, 2015.
  98. Hughes, Sean M; Levy, Claire N; Calienes, Fernanda L; Martinez, Katie A; Selke, Stacy; Tapia, Kenneth; Chohan, Bhavna H; Oluoch, Lynda; Kiptinness, Catherine; Wald, Anna; Ghosh, Mimi; Hardy, Liselotte; Ngure, Kenneth; Mugo, Nelly R; Hladik, Florian; Roxby, Alison C (October 25, 2022). "Starting to have sexual intercourse is associated with increases in cervicovaginal immune mediators in young women: a prospective study and meta-analysis". eLife. 11: e78565. doi:10.7554/eLife.78565. PMC 9596159. PMID 36281966.
  99. Hoeger W, HS, FA, HC (2016). Principles and Labs for Fitness and Wellness. Cengage Learning. pp. 538–540. ISBN 978-1-337-09997-4.
  100. "Sexually transmitted infections". womenshealth.gov. February 22, 2017. Retrieved December 8, 2017.Public Domain This article incorporates text from this source, which is in the public domain.
  101. Gulanick M, Myers JL (2016). Nursing Care Plans - E-Book: Diagnoses, Interventions, and Outcomes. Elsevier Health Sciences. p. 725. ISBN 978-0-323-42810-1.
  102. Murray PR, Rosenthal KS, Pfaller MA (2013). Medical microbiology (7th ed.). St. Louis, MO: Mosby. p. 418. ISBN 978-0-323-08692-9. Archived from the original on December 1, 2015.
  103. Goering, Richard V. (2012). Mims' medical microbiology (5th ed.). Edinburgh: Saunders. p. 245. ISBN 978-0-7234-3601-0.
  104. "STD Trends in the United States: 2010 National Data for Gonorrhea, Chlamydia, and Syphilis". Centers for Disease Control and Prevention. Archived from the original on March 26, 2012. Retrieved September 23, 2023.
  105. ^ "Sexually transmitted infections (STIs)". World Health Organization. Retrieved June 20, 2015.
  106. CDC Hepatitis B Information for Health Professionals Accessed May 27, 2010
  107. "Hepatitis B". World Health Organization. July 18, 2018.
  108. "HIV/AIDS". World Health Organization. Retrieved September 15, 2012.
  109. "HIV/AIDS". Fact sheet N° 360. World Health Organization. July 2012. Retrieved September 8, 2012.
  110. "Not Every Pregnancy is Welcome". The world health report 2005 – make every mother and child count. World Health Organization. Archived from the original on April 14, 2005. Retrieved December 6, 2011.
  111. "Get "In the Know": 20 Questions About Pregnancy, Contraception and Abortion". Guttmacher Institute. 2005. Archived from the original on December 23, 2009. Retrieved March 4, 2011.
  112. Ventura, SJ; Abma, JC; Mosher, WD & Henshaw, S. (November 16, 2007). "Estimated pregnancy rates for the United States, 1990–2000: An Update. National Vital Statistics Reports, 52 (23)" (PDF). Centers for Disease Control and Prevention. Retrieved March 4, 2011.
  113. ^ Blum K, Werner T, Carnes S, Carnes P, Bowirrat A, Giordano J, Oscar-Berman M, Gold M (2012). "Sex, drugs, and rock 'n' roll: hypothesizing common mesolimbic activation as a function of reward gene polymorphisms". Journal of Psychoactive Drugs. 44 (1): 38–55. doi:10.1080/02791072.2012.662112. PMC 4040958. PMID 22641964.
  114. ^ Olsen CM (December 2011). "Natural rewards, neuroplasticity, and non-drug addictions". Neuropharmacology. 61 (7): 1109–1122. doi:10.1016/j.neuropharm.2011.03.010. PMC 3139704. PMID 21459101.
  115. ^ Pitchers KK, Vialou V, Nestler EJ, Laviolette SR, Lehman MN, Coolen LM (February 2013). "Natural and drug rewards act on common neural plasticity mechanisms with ΔFosB as a key mediator". J. Neurosci. 33 (8): 3434–42. doi:10.1523/JNEUROSCI.4881-12.2013. PMC 3865508. PMID 23426671.
  116. Probst, Catharina C.; van Eimeren, Thilo (2013). "The Functional Anatomy of Impulse Control Disorders". Current Neurology and Neuroscience Reports. 13 (10): 386. doi:10.1007/s11910-013-0386-8. ISSN 1528-4042. PMC 3779310. PMID 23963609.
  117. Guilleminault, Christian; Miglis, Mitchell (2014). "Kleine-Levin syndrome: a review". Nature and Science of Sleep. 6: 19–26. doi:10.2147/NSS.S44750. ISSN 1179-1608. PMC 3901778. PMID 24470783.
  118. ^ Nicolas Kipshidze; Jawad Fareed; Patrick W. Serruys; Jeff Moses (2007). Textbook of Interventional Cardiovascular Pharmacology. CRC Press. p. 505. ISBN 978-0-203-46304-8. Retrieved October 21, 2015.
  119. ^ Dahabreh, Issa J. (March 23, 2011). "Association of Episodic Physical and Sexual Activity With Triggering of Acute Cardiac Events. Systematic Review and Meta-analysis". JAMA: The Journal of the American Medical Association. 305 (12): 1225–33. doi:10.1001/jama.2011.336. PMC 5479331. PMID 21427375. Acute cardiac events were significantly associated with episodic physical and sexual activity; this association was attenuated among persons with high levels of habitual physical activity.
  120. ^ John Wincze (2009). Enhancing Sexuality : A Problem-Solving Approach to Treating Dysfunction. Oxford University Press. pp. 56–60. ISBN 978-0-19-971802-3.
  121. ^ Hartmut Porst; Jacques Buvat (2008). Standard Practice in Sexual Medicine. John Wiley & Sons. p. 189. ISBN 978-1-4051-7872-3. Retrieved October 22, 2013.
  122. ^ Emmanuele A. Jannini; Chris G. McMahon; Marcel D. Waldinger (2012). Premature Ejaculation: From Etiology to Diagnosis and Treatment. Springer. pp. 159–162. ISBN 978-88-470-2646-9. Retrieved October 22, 2013.
  123. ^ June M. Reinisch; Ruth Beasley (1991). The Kinsey Institute New Report On Sex. Macmillan. pp. 129–130. ISBN 978-0-312-06386-3. Retrieved August 30, 2012.
  124. Corty EW, Guardiani JM (2008). "Canadian and American Sex Therapists' Perceptions of Normal and Abnormal Ejaculatory Latencies: How Long Should Intercourse Last?". The Journal of Sexual Medicine. 5 (5): 1251–1256. doi:10.1111/j.1743-6109.2008.00797.x. PMID 18331255.
  125. Vern L Bullough; Bonnie Bullough (2014). Human Sexuality: An Encyclopedia. Routledge. p. 32. ISBN 978-1-135-82502-7. Retrieved December 6, 2014.
  126. Rosenthal, Martha (2012). Human Sexuality: From Cells to Society. Cengage Learning. p. 150. ISBN 978-0-618-75571-4. Retrieved October 22, 2013.
  127. ^ Irving B. Weiner; George Stricker; Thomas A. Widiger (2012). Handbook of Psychology, Clinical Psychology. John Wiley & Sons. pp. 172–175. ISBN 978-1-118-40443-0. Retrieved October 22, 2013.
  128. Rod Plotnik; Haig Kouyoumdjian (2010). Introduction to Psychology. Cengage Learning. p. 344. ISBN 978-0-495-90344-4. Inhibited female orgasm refers to a persistent delay or absence of orgasm after becoming aroused and excited. About 10% of women never reach orgasm...
  129. Knoepp LR, Shippey SH, Chen CC, Cundiff GW, Derogatis LR, Handa VL (2010). "Sexual complaints, pelvic floor symptoms, and sexual distress in women over forty". The Journal of Sexual Medicine. 7 (11): 3675–82. doi:10.1111/j.1743-6109.2010.01955.x. PMC 3163299. PMID 20704643.
  130. Fred F. Ferri (2012). Ferri's Clinical Advisor 2013,5 Books in 1, Expert Consult — Online and Print,1: Ferri's Clinical Advisor 2013. Elsevier Health Sciences. p. 1134. ISBN 978-0-323-08373-7. Retrieved November 29, 2014.
  131. ^ Marlene B. Goldman; Rebecca Troisi; Kathryn M. Rexrode (2012). Women and Health. Academic Press. p. 351. ISBN 978-0-12-384979-3. Retrieved December 6, 2014.
  132. Ronald J. Comer (2010). Fundamentals of Abnormal Psychology. Macmillan. p. 338. ISBN 978-1-4292-1633-3. Retrieved December 6, 2014.
  133. ^ Schouten BW, Bohnen AM, Groeneveld FP, Dohle GR, Thomas S, Bosch JL (July 2010). "Erectile dysfunction in the community: trends over time in incidence, prevalence, GP consultation and medication use—the Krimpen study: trends in ED". J Sex Med. 7 (7): 2547–53. doi:10.1111/j.1743-6109.2010.01849.x. PMID 20497307.
  134. "Premature ejaculation". Mayo Clinic.com. Retrieved March 2, 2007.
  135. "Guideline on the pharmacologic management of premature ejaculation" (PDF). American Urological Association. 2004. Archived from the original (PDF) on March 3, 2016. Retrieved October 12, 2013.
  136. Jerrold S Greenberg; Clint E. Bruess; Sara B. Oswalt (2010). Exploring the Dimensions of Human Sexuality. Jones & Bartlett Publishers. p. 633. ISBN 978-0-7637-9740-9. Retrieved December 8, 2014.
  137. Richard Balon; Robert Taylor Segraves (2009). Clinical Manual of Sexual Disorders. American Psychiatric Pub. p. 292. ISBN 978-1-58562-905-3. Retrieved December 6, 2014.
  138. The Architects' Journal. Vol. 221. Architectural Press. 2005. p. 16. Retrieved December 6, 2014.
  139. Richard Balon; Robert Taylor Segraves (2009). Clinical Manual of Sexual Disorders. American Psychiatric Pub. p. 281. ISBN 978-1-58562-905-3. Retrieved December 6, 2014.
  140. Hoffman, Barbara (2012). Williams gynecology (2nd ed.). New York: McGraw-Hill Medical. p. 65. ISBN 978-0-07-171672-7.
  141. "Sexual Health Issues in Men and Cancer Treatment - Side Effects - NCI". www.cancer.gov. September 22, 2017. Retrieved October 21, 2024.
  142. "Sexuality and intimacy". www.cancer.org.au. Retrieved October 21, 2024.
  143. Tristano, Antonio G (2014). "Impact of rheumatoid arthritis on sexual function". World Journal of Orthopedics. 5 (2): 107–11. doi:10.5312/wjo.v5.i2.107. ISSN 2218-5836. PMC 4017303. PMID 24829873.
  144. Deyo, R. A.; Von Korff, M.; Duhrkoop, D. (2015). "Opioids for low back pain". BMJ. 350: g6380. doi:10.1136/bmj.g6380. ISSN 1756-1833. PMC 6882374. PMID 25561513.
  145. Herson, Paco S.; Palmateer, Julie; Hurn, Patricia D. (2012). "Biological Sex and Mechanisms of Ischemic Brain Injury". Translational Stroke Research. 4 (4): 413–419. doi:10.1007/s12975-012-0238-x. ISSN 1868-4483. PMC 3733393. PMID 23930140.
  146. ^ Donna Falvo (2013). Medical and Psychosocial Aspects of Chronic Illness and Disability. Jones & Bartlett Publishers. p. 367. ISBN 978-1-4496-9442-5. Retrieved December 7, 2014.
  147. Alcohol Use and Sexual Risk Behaviour: A Cross-cultural Study in Eight Countries. World Health Organization. 2005. pp. 135 pages. ISBN 978-92-4-156289-8. Retrieved March 30, 2013.
  148. Peter Aggleton; Andrew Ball; Purnima Mane (2013). Sex, Drugs and Young People: International Perspectives. Routledge. pp. 130–133. ISBN 978-1-134-33309-7. Retrieved December 7, 2014.
  149. Medina-Rico, Mauricio; López-Ramos, Hugo; Quiñonez, Andrés (September 1, 2018). "Sexuality in People with Intellectual Disability: Review of Literature". Sexuality and Disability. 36 (3): 231–248. doi:10.1007/s11195-017-9508-6. ISSN 1573-6717. S2CID 255009541.
  150. Greenwood, Nechama W.; Wilkinson, Joanne (2013). "Sexual and Reproductive Health Care for Women with Intellectual Disabilities: A Primary Care Perspective". International Journal of Family Medicine. 2013: 1–8. doi:10.1155/2013/642472. ISSN 2090-2042. PMC 3876698. PMID 24455249.
  151. Harvey, John H.; Wenzel, Amy; Sprecher, Susan (2004). The Handbook of Sexuality in Close Relationships. Psychology Press. pp. 172–173. ISBN 1-135-62470-4.
  152. ^ Victor C. De Munck (1998). Romantic Love and Sexual Behavior: Perspectives from the Social Sciences. Greenwood Publishing Group. pp. 148–149. ISBN 978-0-275-95726-1. Retrieved December 9, 2014.
  153. ^ Tasha R. Howe (2011). Marriages and Families in the 21st Century: A Bioecological Approach. John Wiley & Sons. p. 411. ISBN 978-1-4051-9501-0. Retrieved December 9, 2014.
  154. ^ Mark A Fine; John H. Harvey (2013). Handbook of Divorce and Relationship Dissolution. Psychology Press. p. 160. ISBN 978-1-317-82421-3. Retrieved December 9, 2014.
  155. June M. Reinisch; Ruth Beasley (1991). The Kinsey Institute New Report On Sex. Macmillan. p. 74. ISBN 978-0-312-06386-3. Retrieved December 9, 2014.
  156. Pepper Schwartz; Virginia Rutter (1998). The Gender of Sexuality. Rowman & Littlefield. p. 129. ISBN 978-0-8039-9042-5. Retrieved December 9, 2014.
  157. William Yarber; Barbara Sayad; Bryan Strong (2012). Human Sexuality: Diversity in Contemporary America (Eighth ed.). McGraw-Hill Higher Education. p. 445. ISBN 978-0-07-743525-7. Retrieved December 9, 2014.
  158. Beth Montemurro (2014). Deserving Desire: Women's Stories of Sexual Evolution. Rutgers University Press. p. 169. ISBN 978-0-8135-7306-9. Retrieved December 9, 2014.
  159. Michael Gurian (2013). The Wonder of Aging: A New Approach to Embracing Life After Fifty. Simon & Schuster. p. 178. ISBN 978-1-4767-0671-9. Retrieved December 9, 2014.
  160. ^ Bryan Strong; Theodore Cohen (2013). The Marriage and Family Experience: Intimate Relationships in a Changing Society. Cengage Learning. p. 212. ISBN 978-1-285-53189-2. Retrieved December 9, 2014.
  161. ^ Ponton, Lynn (2000). The Sex Lives of Teenagers. Dutton Publishing. p. 3. ISBN 978-0-452-28260-5.
  162. Ralph J. DiClemente; John S. Santelli; Richard A. Crosby (2009). Adolescent Health: Understanding and Preventing Risk Behaviors. John Wiley & Sons. pp. 521–522. ISBN 978-0-470-45279-0. Retrieved December 7, 2014.
  163. ^ Jamie L Abaied; Deepika Anand; Tracey L Auster; Daniel BE (2014). The Oxford Handbook of Depression and Comorbidity. Oxford University Press. p. 450. ISBN 978-0-19-979700-4. Retrieved December 7, 2014.
  164. Kevin Ryan; James Cooper (2008). Those Who Can, Teach. Cengage Learning. p. 110. ISBN 978-0-547-20488-8. Retrieved December 9, 2014.
  165. ^ Lerner RM, Perkins DF (1999). Social Interactions in Adolescence and Promoting Positive Social Contributions of Youth. Taylor & Francis. p. 124. ISBN 978-0-8153-3295-4. Retrieved April 14, 2017.
  166. ^ Kowalski RM, Leary MR (2004). The Interface of Social and Clinical Psychology: Key Readings. Psychology Press. p. 121. ISBN 978-1-84169-087-2. Retrieved April 14, 2017.
  167. ^ Mary H. Guindon (2009). Self-Esteem Across the Lifespan: Issues and Interventions. Taylor & Francis. p. 147. ISBN 978-1-84169-087-2. Retrieved April 14, 2017.
  168. ^ Lisa Arai (2009). Teenage Pregnancy: The Making and Unmaking of a Problem. Policy Press. p. 147. ISBN 978-1-84742-074-9. Retrieved April 14, 2017.
  169. Madsen S., Collins W. A. (2005). Differential predictions of young adult romantic relationships from transitory vs. longer romantic experiences during adolescence. Presented at Biennial Meeting of the Society for Research on Child Development, Atlanta, Georgia.
  170. Seiffge-Krenke I. [de], Lang J. (2002). Forming and maintaining romantic relations from early adolescence to young adulthood: evidence of a developmental sequence. Presented at 19th Biennial Meeting of the Society for Research on Adolescence, New Orleans, Louisiana.
  171. Pearce MJ, Boergers J, Prinstein MJ (2002). "Adolescent obesity, overt and relational peer victimization, and romantic relationships". Obesity Research. 10 (5): 386–93. doi:10.1038/oby.2002.53. PMID 12006638. S2CID 154577.
  172. Zimmer-Gembeck MJ, Siebenbruner J, Collins WA (2004). "A prospective study of intraindividual and peer influences on adolescents' heterosexual romantic and sexual behavior". Archives of Sexual Behavior. 33 (4): 381–394. doi:10.1023/B:ASEB.0000028891.16654.2c. PMID 15162084. S2CID 1054833.
  173. William N. Eskridge Jr. Dishonorable Passions: Sodomy Laws in America, 1861–2003. (2008) Viking Adult. ISBN 0-670-01862-7
  174. Noelle N. R. Quenivet. Sexual Offenses in Armed Conflict & International Law. (2005) Hotei Publishing. ISBN 1-57105-341-7
  175. Marshall Cavendish Corporation (2010). Sex and Society. Marshall Cavendish Corporation. pp. 143–144. ISBN 978-0-7614-7906-2. Retrieved August 25, 2013.
  176. ^ Jerrold S. Greenberg; Clint E. Bruess; Sarah C. Conklin (2010). Exploring the Dimensions of Human Sexuality. Jones & Bartlett Learning. p. 515. ISBN 978-0-7637-7660-2. Retrieved August 25, 2013.
  177. Karen L. Kinnear (2007). Childhood Sexual Abuse: A Reference Handbook. ABC-CLIO. p. 89. ISBN 978-1-85109-905-4. Retrieved August 25, 2013.
  178. Reed, E. J. (1997). "Criminal Law and the Capacity of Mentally Retarded Persons to Consent to Sexual Activity". Virginia Law Review. 83 (4): 799–827. doi:10.2307/1073749. JSTOR 1073749.
  179. ^ Francoeur RT, Noonan RJ, Opiyo-Omolo B (2004). The Continuum Complete International Encyclopedia of Sexuality. Continuum International Publishing Group. p. 173. ISBN 978-0-8264-1488-5. Retrieved April 30, 2013.
  180. Ken Plummer (2002). Modern Homosexualities: Fragments of Lesbian and Gay Experiences. Routledge. pp. 187–191. ISBN 978-1-134-92242-0. Retrieved August 24, 2013. ome sexual practices are regarded as inherently better (normal, natural, more satisfying) than others, with vaginal intercourse privileged as the 'Real Thing.' Such beliefs, influenced by views about sex as ultimately a reproductive function, continue to be perpetuated through discourses on sex despite a number of important contradictions.
  181. "An Updated Definition of Rape (U.S. Dept of Justice, January 6, 2012)". Archived from the original on March 13, 2012. Retrieved October 30, 2014.
  182. Savage, Charlie (January 6, 2012). "U.S. to Expand Rape Definition in Crime Statistics". The New York Times.
  183. Smith, Merril D., ed. (2004). Encyclopedia of rape (1st ed.). Westport, Conn.: Greenwood Press. pp. 169–170. ISBN 978-0-313-32687-5.
  184. "Dr James Roffee". Monash university. Archived from the original on February 4, 2017. Retrieved May 22, 2017.
  185. Roffee, J. A. (September 2014). "No Consensus on Incest? Criminalisation and Compatibility with the European Convention on Human Rights". Human Rights Law Review. 14 (3): 541–572. doi:10.1093/hrlr/ngu023.
  186. Diagnostic and Statistical Manual of Mental Disorders: DSM-IV. Washington, DC: American Psychiatric Association. 2000. ISBN 978-0-89042-025-6.
  187. Milner JS, Dopke CA (2008). "Paraphilia Not Otherwise Specified: Psychopathology and theory". In Laws DR, O'Donohue WT (eds.). Sexual Deviance, Second Edition: Theory, Assessment, and Treatment. New York: The Guilford Press. pp. 384–418. ISBN 978-1-59385-605-2.
  188. Seto, MC; Barbaree HE (2000). "Paraphilias". In Hersen M; Van Hasselt VB (eds.). Aggression and violence: an introductory text. Boston: Allyn & Bacon. pp. 198–213. ISBN 978-0-205-26721-7.
  189. Abigail Perdue; Randall Lockwood (2014). Animal Cruelty and Freedom of Speech: When Worlds Collide. Purdue University Press. pp. 6–8. ISBN 978-1-55753-633-4. Retrieved December 9, 2014.
  190. Margaret Monahan Hogan (2002). Marriage as a Relationship: Real and Rational. Marquette University Press. p. 88. ISBN 978-0-87462-657-5. Retrieved September 1, 2015.
  191. ^ James G. Dwyer (2001). Religious Schools V. Children's Rights. Cornell University Press. pp. 72–73. ISBN 978-0-8014-8731-6. Retrieved August 31, 2015.
  192. Ronald Green (2013). Religion and Sexual Health: Ethical, Theological, and Clinical Perspectives, Volume 1 of Theology and Medicine. Springer Science & Business Media. p. 112. ISBN 978-94-015-7963-6. Retrieved August 31, 2015.
  193. Heather Brook (2015). Conjugality: Marriage and Marriage-like Relationships Before the Law. Palgrave Macmillan. pp. 71–73. ISBN 978-1-137-48091-0. Retrieved August 31, 2015.
  194. Suzanne K. Steinmetz; Marvin B. Sussman (2013). Handbook of Marriage and the Family. Springer Science & Business Media. pp. 787–788. ISBN 978-1-4615-7151-3. Retrieved August 31, 2014.
  195. Oshisanya, 'lai Oshitokunbo (2015). An Almanac of Contemporary Judicial Restatements (Criminal & Quasi Criminal Law & Procedure) vol. iii: Almanac vol. iii. Almanac Foundation. p. 132. ISBN 978-978-51200-3-5. Retrieved August 31, 2015.
  196. James A. Brundage (2009). Law, Sex, and Christian Society in Medieval Europe. University of Chicago Press. pp. 609–611. ISBN 978-0-226-07789-5. Retrieved August 31, 2015.
  197. Philip Carlan; Lisa S. Nored; Ragan A. Downey (2011). An Introduction to Criminal Law. Jones & Bartlett Publishers. p. 139. ISBN 978-1-4496-4721-6. Retrieved August 31, 2015.
  198. "Can Iran 'control' its cohabiting couples?". BBC News. December 10, 2014. Retrieved August 31, 2015.
  199. "Amnesty International Report 2014/15". amnesty.org. 2014. Archived from the original on May 4, 2017. Retrieved August 31, 2015.
  200. "Share of live births outside marriage". europa.eu. March 2, 2015. Retrieved August 31, 2015.
  201. Choudhri, Nihara K (2004). The complete guide to divorce law. Citadel Press. pp. 8–9. ISBN 978-0-8065-2528-0. Retrieved August 30, 2015.
  202. "Blanchflower v. Blanchflower and Mayer". Gay & Lesbian Advocates & Defenders (GLAD). December 31, 2003. Archived from the original on November 21, 2016. Retrieved August 9, 2013.
  203. "In the Matter of David G. Blanchflower and Sian E. Blanchflower". New Hampshire Judicial Branch. November 7, 2003. Archived from the original on February 12, 2004. Retrieved September 3, 2023.
  204. Janet Afary. Sexual Politics in Modern Iran. (2009) Cambridge University Press. ISBN 0-521-89846-3
  205. "PUBLIC AI Index: MDE 13/010/2008. UA 17/08 Fear of imminent execution/ flogging". Amnesty International. Archived from the original on March 5, 2016. Retrieved December 22, 2013.
  206. Naomi R. Cahn; June Carbone (2010). Red families v. blue families: legal polarization and the creation of culture. Oxford University Press US. p. 129. ISBN 978-0-19-537217-5. Retrieved July 29, 2011.
  207. ^ Donald J. Cantor (2006). Same-sex marriage: the legal and psychological evolution in America. Wesleyan University Press. pp. 1–191. ISBN 978-0-8195-6812-0. Retrieved July 29, 2011.
  208. ^ American Psychological Association (2004). "Resolution on Sexual Orientation and Marriage" (PDF). Retrieved September 1, 2015.
  209. ^ Daniel L. Akin (2003). God on Sex: The Creator's Ideas About Love, Intimacy, and Marriage. B&H Publishing Group. pp. 1–291. ISBN 978-0-8054-2596-3. Retrieved October 21, 2015.
  210. ^ Dennis P. Hollinger (2009). The Meaning of Sex: Christian Ethics and the Moral Life. Baker Academic. pp. 30–33. ISBN 978-0-8010-3571-5. Retrieved December 9, 2014.
  211. Chad Denton (2014). The War on Sex: Western Repression from the Torah to Victoria. McFarland. pp. 107–117. ISBN 978-0-547-20488-8. Retrieved December 9, 2014.
  212. ^ Margaret D. Kamitsuka (2010). The Embrace of Eros: Bodies, Desires, and Sexuality in Christianity. Fortress Press. pp. 16–17. ISBN 978-1-4514-1351-9. Retrieved December 9, 2014.
  213. Stefanie Knauss (2014). More Than a Provocation: Sexuality, Media and Theology. Vandenhoeck & Ruprecht. p. 69. ISBN 978-3-525-60450-2. Retrieved December 9, 2014.
  214. Robert G. Barnes; Rosemary J. Barnes (1996). Great Sexpectations: Finding Lasting Intimacy in Your Marriage. Zondervan. p. 66. ISBN 978-0-310-20137-3. Retrieved December 9, 2014.
  215. Christo Scheepers (2012). Between the Covers: Sexual freedom through the bond of marriage. Struik Christian Media. p. 53. ISBN 978-1-4153-2056-3. Retrieved December 9, 2014.
  216. Jill Oliphant (2010). OCR Religious Ethics for AS and A2. Routledge. p. 213. ISBN 978-1-136-99291-9. Retrieved September 1, 2015.
  217. D. L. d'Avray (2010). Rationalities in History: A Weberian Essay in Comparison. Cambridge University Press. pp. 177–178. ISBN 978-1-139-49050-4. Retrieved September 1, 2015.
  218. William H. Swatos; Peter Kivisto (1998). Encyclopedia of Religion and Society. Rowman Altamira. p. 464. ISBN 978-0-7619-8956-1. Retrieved December 9, 2014.
  219. Chase, Stacey (July 23, 2006). "The Last Ones Standing". The Boston Globe. Archived from the original on August 13, 2006. Retrieved July 26, 2023.
  220. Laura J. Zilney; Lisa Anne Zilney (2009). Perverts and Predators: The Making of Sexual Offending Laws. Rowman & Littlefield. pp. 7–8. ISBN 978-0-7425-6624-8. Retrieved December 9, 2014.
  221. ^ Don S. Browning, Martha Christian Green, John Witte. Sex, marriage, and family in world religions. (2006) Columbia University Press. ISBN 0-231-13116-X
  222. Abdul Rahman bin Abdul Karim al-Sheha. Islamic Perspective of Sex (2003) Saudi Arabia. ISBN 9960-43-140-1
  223. Fatima M. D'Oyen. The Miracle of Life. (2007) Islamic Foundation (UK). ISBN 0-86037-355-X
  224. "Polygamy". All About Shias. July 15, 2015. Retrieved September 7, 2024.
  225. Sharma, Arvind (1999). "The Puruṣārthas: An Axiological Exploration of Hinduism". The Journal of Religious Ethics. 27 (2): 223–256. doi:10.1111/0384-9694.00016. ISSN 0384-9694. JSTOR 40018229.
  226. Harvey, Peter. An Introduction to Buddhist Ethics: Foundations, Values and Issues. Cambridge, 2000: 71-72.
  227. Harvey, Peter. An Introduction to Buddhist Ethics: Foundations, Values and Issues. Cambridge, 2000: 71-74.
  228. Kenneth E. Bowers. God Speaks Again: An Introduction to the Baháʼí Faith. (2004) Baháʼí Publishing. ISBN 1-931847-12-6
  229. John A. Buehrens and Forrest Church. A Chosen Faith: An Introduction to Unitarian Universalism. (1998) Beacon Press. ISBN 0-8070-1617-9
  230. Hodgkinson, Liz (2002). Peace and Purity: The Story of the Brahma Kumaris a Spiritual Revolution. HCI. pp. 2–29. ISBN 978-1-55874-962-7.
  231. Babb, Lawrence A. (1987). Redemptive Encounters: Three Modern Styles in the Hindu Tradition (Comparative Studies in Religion and Society). Oxford University Press. ISBN 0-7069-2563-7. "Sexual intercourse is unnecessary for reproduction because the souls that enter the world during the first half of the Cycle are in possession of a special yogic power (yog bal) by which they conceive children."
  232. Barrett, David V (2001). The New Believers. Cassell & Co. pp. 265. ISBN 0-304-35592-5.
  233. Thompson, Lady Gwen; Wiccan-Pagan Potpourri; Green Egg, №69; Ostara 1974
  234. Hans Holzer. The Truth about Witchcraft (1971) Doubleday. page 128. ISBN 0-09-004860-1
  235. Baba, Meher (1995). Discourses. Myrtle Beach: Sheriar Press. p. 109. ISBN 978-1-880619-09-4.
  236. William Skudlarek [de]. Demythologizing Celibacy: Practical Wisdom from Christian and Buddhist Monasticism. (2008) Liturgical Press. ISBN 0-8146-2947-4
  237. Ruppert, E.E.; Fox, R.S. & Barnes, R.D. (2004). "Chelicerata: Araneae". Invertebrate Zoology (7th ed.). Brooks/Cole. pp. 571–584. ISBN 978-0-03-025982-1.
  238. Cecie Starr; Christine Evers; Lisa Starr (2010). Cengage Advantage Books: Biology: A Human Emphasis. Cengage Learning. pp. 630–631. ISBN 978-1-133-17005-1. Retrieved December 9, 2010.
  239. Edward J. Denecke Jr. (2006). New York State Grade 8 Intermediate Level Science Test. Barron's Educational Series. p. 105. ISBN 978-0-7641-3433-3. Retrieved December 9, 2014.
  240. M. Yadav (2003). Breeding in Insects. Discovery Publishing House. p. 59. ISBN 978-81-7141-737-7. Retrieved December 9, 2014.
  241. Franz Engelmann (2013). The Physiology of Insect Reproduction: International Series of Monographs in Pure and Applied Biology: Zoology. Elsevier. pp. 58–59. ISBN 978-1-4831-8653-5. Retrieved December 9, 2014.
  242. Janet Leonard; Alex Cordoba-Aguilar (2010). The Evolution of Primary Sexual Characters in Animals. Oxford University Press. p. 334. ISBN 978-0-19-971703-3. Retrieved December 9, 2014.
  243. P. J. Gullan; P. S. Cranston (2009). The Insects: An Outline of Entomology. John Wiley & Sons. p. 124. ISBN 978-1-4051-4457-5. Retrieved December 9, 2014.

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