Editing Human sexuality (section)

===General activities and health===
{{Main|Human sexual activity}}
{{See also|Sexual intercourse#Health effects|Sexually active life expectancy}}

In humans, sexual intercourse and sexual activity {{citation needed|date=December 2020}} in general have been shown to have health benefits, such as an improved sense of smell,{{citation needed|date=June 2016}} reduction in [[Stress (biology)|stress]] and blood pressure,<ref name="webmd.com">Doheny, K. (2008) [http://www.webmd.com/sex-relationships/features/10-surprising-health-benefits-of-sex "10 Surprising Health Benefits of Sex,"] [[WebMD]] (reviewed by Chang, L., M.D.)</ref><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> increased [[immune system|immunity]],<ref>Charnetski CJ, Brennan FX. Sexual frequency and salivary immunoglobulin A (IgA). ''Psychological Reports'' 2004 Jun;94(3 Pt 1):839–844. Data on length of relationship and sexual satisfaction were not related to the group differences.</ref> and decreased risk of [[prostate cancer]].<ref>Michael F. Leitzmann; Edward Giovannucci. Frequency of Ejaculation and Risk of Prostate Cancer – Reply. ''JAMA''. (2004);292:329.</ref><ref>Leitzmann MF, Platz EA, Stampfer MJ, Willett WC, Giovannucci E. Ejaculation Frequency and Subsequent Risk of Prostate Cancer. ''JAMA''. (2004);291(13):1578–1586.</ref><ref>{{cite journal | pmid = 12887469 | volume=92 | issue=3 | title=Sexual factors and prostate cancer | date=August 2003 | journal=BJU Int. | pages=211–216 | last1 = Giles | first1 = GG | last2 = Severi | first2 = G | last3 = English | first3 = DR | display-authors = etal  | doi=10.1046/j.1464-410x.2003.04319.x| s2cid=29430415 | doi-access=free }}</ref> Sexual intimacy and orgasms increase levels of oxytocin, which helps people bond and build trust.<ref>{{cite journal | pmid = 19482229 | doi=10.1016/j.pneurobio.2009.04.001 | volume=88 | issue=2 | title=Oxytocin: the great facilitator of life | pmc=2689929 | date=June 2009 | journal=Prog. Neurobiol. | pages=127–151 | last1 = Lee | first1 = HJ | last2 = Macbeth | first2 = AH | last3 = Pagani | first3 = JH | last4 = Young | first4 = WS}}</ref><ref>Riley AJ. Oxytocin and coitus. ''Sexual and Relationship Therapy'' (1988);3:29–36</ref><ref>Carter CS. Oxytocin and sexual behavior. ''Neuroscience & Biobehavioral Reviews'' (1992);16(2):131–144</ref>

A long-term study of 3,500 people between ages 30 and 101 by clinical neuropsychologist David Weeks, MD, head of old-age psychology at the [[Royal Edinburgh Hospital]] in Scotland, said he found that "sex helps you look between four and seven years younger", according to impartial ratings of the subjects' photographs. Exclusive causation, however, is unclear, and the benefits may be indirectly related to sex and directly related to significant reductions in stress, greater contentment, and better sleep that sex promotes.<ref>{{cite web|last=Blum|first=Jeffrey |title=Can Good Sex Keep You Young?|url=http://www.medicinenet.com/script/main/art.asp?articlekey=51501|website=WebMD|access-date=8 October 2010}}</ref><ref>{{cite book|last=Weeks|first=David|title=Secrets of the Superyoung|year=1999|publisher=Berkley|isbn=978-0-425-17258-2|page=[https://archive.org/details/isbn_9780425172582/page/277 277]|url=https://archive.org/details/isbn_9780425172582/page/277}}</ref><ref>{{cite book|last=Northrup|first=Christiane|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=960|url={{Google books |plainurl=yes |id=V9S3keMnie8C |page=232 }} }}</ref>

Sexual intercourse can also be a [[vector (epidemiology)|disease vector]].<ref>"[http://www.4parents.gov/sexrisky/stds/common_std/common_std.html Common Sexually Transmitted Diseases (STDs)] {{webarchive|url=https://web.archive.org/web/20110625104729/http://www.4parents.gov/sexrisky/stds/common_std/common_std.html |date=25 June 2011 }}". U.S. Department of Health & Human Services.</ref> There are 19 million new cases of sexually transmitted diseases (STD) every year in the U.S.,<ref name="CDC">Centers for Disease Control and Prevention. [https://www.cdc.gov/std/stats08/surv2008-Complete.pdf Sexually Transmitted Disease Surveillance], 2008. Atlanta, GA: U.S. Department of Health and Human Services; November 2009.[https://www.cdc.gov/std/stats08/2008survFactSheet.PDF Fact Sheet]</ref> and worldwide there are over 340 million STD infections each year.<ref name="who">World Health Organization Fact Sheet on Sexually Transmitted Diseases. {{cite web |url=https://www.who.int/mediacentre/factsheets/fs110/en/print.html |title=Archived copy |access-date=24 July 2011 |url-status=dead |archive-url=https://web.archive.org/web/20120709030847/http://www.who.int/mediacentre/factsheets/fs110/en/print.html |archive-date=9 July 2012  }} Accessed 27 May 2010</ref> More than half of these occur in adolescents and young adults aged 15–24 years.<ref>Weinstock H, et al. Sexually transmitted diseases among American youth: incidence and prevalence estimates, 2000. ''Perspectives on Sexual and Reproductive Health'' (2004);36(1):6–10.</ref> At least one in four U.S. teenage girls has a sexually transmitted disease.<ref name="CDC"/><ref>[https://www.nytimes.com/2008/03/12/science/12std.html?_r=1 Sex Infections Found in Quarter of Teenage Girls]. [[The New York Times]]. 12 March 2008.</ref> In the U.S., about 30% of 15- to 17-year-olds have had sexual intercourse, but only about 80% of 15- to 19-year-olds report using condoms for their first sexual intercourse.<ref>CDC. Sexual and Reproductive Health of Persons Aged 10–24 Years – United States, 2002–2007. MMWR 20009; 58 (No. SS-6):1–59 [https://www.cdc.gov/mmwr/pdf/ss/ss5806.pdf]</ref> In one study, more than 75% of young women age 18–25 years felt they were at low risk of acquiring an STD.<ref>{{cite journal | pmid = 12855216 | volume=37 | issue=2 | title=Factors associated with condom use among at-risk women students and nonstudents seen in managed care | date=August 2003 | journal=Prev Med | pages=163–170 | last1 = Yarnall | first1 = KS | last2 = McBride | first2 = CM | last3 = Lyna | first3 = P | display-authors = etal  | doi=10.1016/s0091-7435(03)00109-9}}</ref>