Voltaire ridiculed in Candide the idea that everything has been created for the best possible purpose. “Note that noses were made to wear glasses, that’s why we wear glasses,” said his character, the optimistic Professor Pangloss.
According to that first view of biological evolution, which Darwin and Wallace would describe a century later, all the features of the species served, like Pangloss’s noses, an advantageous purpose. In the second half of the 20th century, paleontologist Stephen Jay Gould introduced the idea that utility could appear later, as with Pangloss glasses.
In two previous articles, Why are men the primates with the biggest penis? and Why is human childbirth so painful? , I dealt with some of the changes brought about in the human lineage as a consequence of the evolutionary tendency towards standing that distinguishes the genus Homo among primates.
In both, I emphasized that walking on the lower extremities had altered the form of copulation, which in humans is frontal, face to face, an exceptional circumstance in mammals (except for its occasional practice by bonobos). Also the characteristics of our paroxysmal orgasm, whose evolutionary importance has been discussed, but which can be interpreted as another adaptation to standing.
Despite its neuro-endocrine-muscular complexity, the male orgasm can be summarized as a complex chain of contracting movements that culminate in a sudden sensation of intense pleasure. This is accompanied by ejaculation, a violent ejection of fluid that drives sperm into the vagina.
In men, orgasm is a mandatory requirement for ejaculation to occur, but women do not need it either to produce each of the 300 monthly eggs they produce during their fertile life, or to have children.
So what function does the female orgasm have from an evolutionary point of view? Although it has been a social taboo and a biological enigma, some evidence allows to clarify the matter.
In his book Sex Alone, Berkeley professor Thomas Laqueur argues that “from ancient times to the nineteenth century, the general assumption was that women experienced orgasms just like men, but also that orgasm was necessary for conception.”
If the first is absolutely true, the second is wrong. This was advanced in 1967 by the zoologist Desmond Morris in The Naked Monkey and also demonstrated by the studies of Masters and Johnson, based on ten thousand human sexual acts ( Human sexuality ).
This confirmed that what causes the female orgasm in most cases is the stimulation of the clitoris. An area that is not contacted by the penis during copulation and therefore does not intervene in the insemination process.
In the essay Male nipples and clitoral waves , part of the book Brontosaurus and the minister’s buttock, Stephen Jay Gould argued that, as the important thing is that the sperm reach the ovules and to achieve this, the male orgasm is enough, the female one should be contemplated as “superfluous”. Some kind of evolutionary accident, a secondary result of the need for the male orgasm.
According to Gould, there is a female orgasm simply because the clitoris is the anatomical equivalent of the penis (both have the same embryonic origin). Therefore, stimulation, erection and orgasm occur in both. For Gould, orgasm via the clitoris is a developmental artifact. It has no adaptive significance.
Gould’s controversy was resurrected in 2005 when Elisabeth Lloyd, Professor of Philosophy of Science at Indiana University, published a book, The Case of the Female Orgasm: Bias in Evolutionary Science. evolution). In this he concludes that the female orgasm does not have any evolutionary sense (except to enjoy, which is not little). Like Gould, he considers it to be a by-product of evolution.
The idea of the “evolutionary by-product” is Darwin’s, who considered it as any trait that is drawn from others. Men’s nipples are a clear example. We possess them because we share with women the same architecture fixed by a common embryonic design, until the appearance of testosterone and estrogens directs the undifferentiated fetus towards one or the other sex. While in women they are used for lactation, in men they would be a by-product with no adaptive value whatsoever.
But this does not necessarily apply to the female orgasm.
To begin with, pleasure in sex has developed in both sexes. This pleasure is the proximate cause of sexual intercourse, the ultimate goal of which is reproductive success. If we also consider the patterns that characterize the female orgasm, the conclusion is even less convincing.
During orgasm in both sexes there are considerable increases in the pulsations (from 70 to 80 to 150 beats per minute), in blood pressure (from 120 to 250 mmHg at climax) and in breathing, which becomes deeper and fast until, as the moment of orgasm approaches, she becomes panting. In the end, the face contracts, with the mouth wide open and the nostrils dilated, in the manner of athletes in their maximum effort, already short of air.
What distinguishes the female orgasm are a series of rhythmic contractions in the perineal area, the vagina and the uterus. Such contractions have an absorbent function of the sperm described by Baker and Bellis in the journal Animal Behavior that, in addition, increases their retention in the vaginal canal, as Paul R. Ehrich argues in Human natures: Genes, Cultures, and the Human Prospect. Human: Genes, Cultures and the Human Perspective; not published in Spanish). For this reason, the evolutionary hypotheses that have the most support among scientists refer to the role of orgasm as a mechanism of retention of sperm within the female sexual tract.
Finally, if we consider that orgasm is followed by a considerable period of exhaustion and sleep, it can be deduced that another of its adaptive functions is to induce horizontal rest after copulation. This favors the retention of sperm and thus increases the woman’s chances of being fertilized.
This postcoital indolence, followed or not by the repairing cigarette, is another difference of the human orgasm with respect to other primates, which is fundamental in the female of the only mammal whose vagina, as a consequence of the acquisition of the upright gait, opens in position vertical. This favors, with all due respect, the gravitational fall of the spermatic fluid.
Manuel Peinado Lorca. University professor. Department of Life Sciences and Researcher at the Franklin Institute for North American Studies, University of Alcalá
This article was originally published on The Conversation. Read the original.
