Editing Orgasm (section)

=== Adaptive or vestigial ===

The clitoris is [[homology (biology)|homologous]] to the penis; that is, they both develop from the same embryonic structure.<ref name="Schünke" /><ref name="Francoeur" /> While researchers such as [[Geoffrey Miller (psychologist)|Geoffrey Miller]], [[Helen Fisher (anthropologist)|Helen Fisher]], [[Meredith Small]] and [[Sarah Blaffer Hrdy]] "have viewed the clitoral orgasm as a legitimate adaptation in its own right, with major implications for female sexual behavior and sexual evolution,"<ref name="Geoffrey Miller" /> others, such as [[Donald Symons]] and [[Stephen Jay Gould]], have asserted that the clitoris is [[vestigiality|vestigial]] or nonadaptive and that the female orgasm serves no particular evolutionary function.<ref name="Geoffrey Miller" /><ref name="Gould" /> Gould acknowledged that "most female orgasms emanate from a clitoral, rather than vaginal (or some other), site" and stated that his nonadaptive belief "has been widely misunderstood as a denial of either the adaptive value of female orgasm in general or even as a claim that female orgasms lack significance in some broader sense". He explained that although he accepts that "clitoral orgasm plays a pleasurable and central role in female sexuality and its joys," "[a]ll these favorable attributes, however, emerge just as clearly and just as easily, whether the clitoral site of orgasm arose as a [[Spandrel (biology)|spandrel]] or an adaptation". He said that the "male biologists who fretted over [the adaptionist questions] simply assumed that a deeply vaginal site, nearer the region of fertilization, would offer greater selective benefit" due to their Darwinian, ''[[summum bonum]]'' beliefs about enhanced reproductive success.<ref name="Gould" />

Proponents of the nonadaptive hypothesis, such as Elisabeth Lloyd, refer to the relative difficulty of achieving female orgasm through vaginal sex, the limited evidence for increased fertility after orgasm, and the lack of statistical correlation between the capacity of a woman to orgasm and the likelihood that she will engage in intercourse.<ref name="Lloyd" /><ref name="Chivers">{{cite journal |first1 = Meredith L. |last1 = Chivers |first2 = Michael W. |last2 = Wiedermana |title = A Narrow (But Thorough) Examination of the Evolutionary Significance of Female Orgasm |journal = [[Journal of Sex Research]] |volume = 44 |issue = 1 |pages = 104–105 |date = 2007 |doi = 10.1080/00224490709336797 |df = mdy-all }}</ref> "Lloyd is by no means against evolutionary psychology. Quite the opposite; in her methods and in her writing, she advocates and demonstrates a commitment to the careful application of evolutionary theory to the study of human behavior," stated [[Meredith Chivers|Meredith L. Chivers]]. She added that Lloyd "meticulously considers the theoretical and empirical bases for each account and ultimately concludes that there is little evidence to support an adaptionist account of female orgasm" and that Lloyd instead "views female orgasm as an ontogenetic leftover; women have orgasms because the urogenital neurophysiology for orgasm is so strongly selected for in males that this developmental blueprint gets expressed in females without affecting fitness, just as males have nipples that serve no fitness-related function".<ref name="Chivers" />

A 2005 [[twin study]] found that one in three women reported never or seldom achieving orgasm during sexual intercourse, and only one in ten always orgasmed. This variation in the ability to orgasm, generally thought to be psychosocial, was found to be 34 percent to 45 percent genetic. The study, examining 4000 women, was published in ''[[Biology Letters]]'', a [[Royal Society]] journal.<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/health/4616899.stm |title=Female orgasm is 'down to genes{{'-}} |work=[[BBC]] |date=June 7, 2005 |access-date=May 28, 2006 |url-status=live |archive-url=https://web.archive.org/web/20161021184246/http://news.bbc.co.uk/2/hi/health/4616899.stm |archive-date=October 21, 2016  }}</ref><ref>{{cite journal |last1 = Dunn |first1 = Kate M |last2 = Cherkas |first2 = Lynn F |last3 = Spector |first3 = Tim D |title = Genetic influences on variation in female orgasmic function: a twin study |journal = Biology Letters |type = Abstract |date = September 22, 2005 |volume = 1 |issue = 3 |pages = 260–263 |doi = 10.1098/rsbl.2005.0308 |pmc = 1617159 |pmid = 17148182 }}</ref> Elisabeth Lloyd has cited this as evidence for the notion that female orgasm is not adaptive.<ref name="Lloyd" /><ref name="Lloyd2">{{cite web |url = http://mypage.iu.edu/%7Eealloyd/Reviews.html#IsntItObviousThat |title = Reviews |publisher = Mypage.iu.edu |access-date = October 15, 2010 |archive-date = April 1, 2020 |archive-url = https://web.archive.org/web/20200401223451/http://mypage.iu.edu/~ealloyd/Reviews.html#IsntItObviousThat |url-status = dead }}</ref>

Miller, Hrdy, Helen O'Connell, and [[Natalie Angier]] have criticized the "female orgasm is vestigial" hypothesis as understating and devaluing the psychosocial value of the female orgasm.<ref name="Geoffrey Miller" /> Hrdy stated that the hypothesis smacks of [[sexism]].<ref>{{cite news |author = Christopher Shea |title = Orgasmic science |work = The Boston Globe |date = April 24, 2005 }}</ref> O'Connell said, "It boils down to rivalry between the sexes: the idea that one sex is sexual and the other reproductive. The truth is that both are sexual and both are reproductive."<ref name="O'Connell" /> O'Connell used [[Magnetic resonance imaging|MRI]] technology to define the true size and shape of the clitoris, suggesting that it extends into the anterior wall of the vagina ([[#Females|see above]]).

O'Connell describes typical textbook descriptions of the clitoris as lacking detail and including inaccuracies, saying that the work of [[Georg Ludwig Kobelt]] in the early 19th century provides a most comprehensive and accurate description of clitoral anatomy. She argues that the bulbs appear to be part of the clitoris and that the distal urethra and vagina are intimately related structures, although they are not erectile in character, forming a tissue cluster with the clitoris that appears to be the center of female sexual function and orgasm.<ref name="O'Connell" /> By contrast, Nancy Tuana, at the 2002 conference for ''Canadian Society of Women in Philosophy'', argues that the clitoris is unnecessary in reproduction, but that this is why it has been "historically ignored", mainly because of "a fear of pleasure. It is pleasure separated from reproduction. That's the fear". She reasoned that this fear is the cause of the ignorance that veils female sexuality.<ref name="Cairney">{{cite web |last = Cairney |first = Richard |title = Exploring female sexuality |publisher = ExpressNews |date = October 21, 2002 |access-date = December 21, 2011 |url = http://www.expressnews.ualberta.ca/article.cfm?id=3201 |archive-date = December 21, 2011 |archive-url = https://web.archive.org/web/20111221175533/http://www.archives.expressnews.ualberta.ca/article/2002/10/3201.html }}</ref>