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How Orgasms Work

        Health | Sexuality

The Female Orgasm Debate Continues: Byproduct Theory
Do female orgasms exist for the same reason men have nipples?
Do female orgasms exist for the same reason men have nipples?
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Supporters of the byproduct theory liken the female orgasm to male nipples [source: Yoder]. As fetuses develop, all are outfitted with the anatomical precursors to nipples, although they only offer a direct reproductive advantage to women for feeding their babies. But since that's such a favorable trait, evolution didn't go to the painstaking trouble of weeding nipples out of the male population. In other words, men have nipples because women do. Likewise, clitoral and penile tissues are borne of the same embryological stuff, developing into one or the other once biological sex traits set in. The hooded glans, packed with 8,000 nerve endings, is just the visible tip of the internal clitoral structure that extends up and around the vagina and engorges during arousal much like the penis [source: Gonzalez]. Therefore, female orgasms could exist because that clitoral anatomy was under no evolutionary pressure to disappear.

A pair of 2011 studies led by Brendan P. Zietsch at Australia's University of Queensland exemplifies why reconciling the two camps -- adaptive and byproduct -- has remained implausible. In one study of orgasmic function among 1,457 sets of female twins, Zietsch and his colleagues found no correlation between female orgasmic function and 19 other evolutionarily significant traits, including impulsiveness, risky sexual behavior and masculinity [source: Zietsch et al]. One point for team byproduct.

Then, Zietsch's team conducted a follow-up study comparing the orgasmic function of opposite-sex twins, since they share identical genetic information, hypothetically putting them on an even orgasmic playing field. According to byproduct theory, the self-reporting should've resulted in twins with matching self-reported rates of orgasms. For same-sex sets in the study, that was the case. But brother-sister pairs had no such luck. Sisters consistently tallied up fewer than their brothers, effectively tipping the hat back toward adaptation [source: Keim].

Chances are, however, the more burning question on lay people's minds regarding women and sex relates not to the orgasmic sensations, but rather their byproduct.


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