After baffling biologists for decades, the female orgasm has resisted yet another attempt to explain its elusive evolutionary origins.
A survey of orgasmic function in thousands of twins found none of the statistical patterns expected if female orgasm is just a coincidental byproduct of natural selection on its male counterpart, as has been suggested.
“The evolutionary basis of human female orgasm has been subject to furious scientific debate, which has recently intensified,” wrote University of Queensland geneticist Brendan Zietsch and Pekka Santtila of Finland’s Abo Akedemi University in a Sept. 3 Animal Behavior article. “These results challenge the byproduct theory of female orgasm.”
While the male orgasm is, in evolutionary and practical terms, a fairly straightforward thing — it makes men want to have sex more often, thus continuing their lineage, and is achieved with ease — the female orgasm is a far trickier beast.
Unlike male orgasm, which is found across the primate spectrum, female orgasm has skipped some species. (Lady gibbons, for example, are out of luck.) In humans, men are far more likely to experience orgasm than women, of whom one in 10 don’t ever experience it.
That imbalance runs contrary to traditional explanations of female orgasm: that it strengthens bonds between mates and thus improves the care received by their children, or that the ability to elicit orgasm indicates a male’s virility, or that underlying physiological processes somehow improve reproductive success.