The role of female orgasm, which plays no obvious role in human reproduction, has intrigued scholars as far back as Aristotle. But most have concentrated on its role in human and primate biology.
But Yale scientists claim to have finally discovered the answer and it’s all about ovulation. Professor Gunter Wagner and Mihaela Pavličev believe that in the past, our female ancestors only released an egg after being stimulated by a male just before or during sex. They found that in many mammals this reflex plays a role in ovulation.
Will you offer us a hand? Every gift, regardless of size, fuels our future.
Your critical contribution enables us to maintain our independence from shareholders or wealthy owners, allowing us to keep up reporting without bias. It means we can continue to make Jewish Business News available to everyone.
You can support us for as little as $1 via PayPal at office@jewishbusinessnews.com.
Thank you.
Once stimulated, the prehistoric female would have released certain hormones – prolactin and oxytocin – causing her to ovulate and the egg was then fertilised by sperm. But over hundreds of thousands of years their bodies evolved to ovulate by themselves – once a month.
Since there is no apparent association between orgasm and number of offspring or successful reproduction in humans, the scientists focused on a specific physiological trait that accompanies human female orgasm and looked for this activity in other placental mammals.
In spite of the enormous diversity of mammalian reproductive biology, some core characteristics can be traced throughout mammalian evolution, note the researchers. The female ovarian cycle in humans, for instance, is not dependent upon sexual activity. However, in other mammalian species ovulation is induced by males. The scientists’ analysis shows male-induced ovulation evolved first and that cyclical or spontaneous ovulation is a derived trait that evolved later.
The scientists suggest that female orgasm may have evolved as an adaptation for a direct reproductive role — the reflex that, ancestrally, induced ovulation. This reflex became superfluous for reproduction later in evolution, freeing female orgasm for secondary roles.
A comparative study of female genitalia also revealed that, coincidental with the evolution of spontaneous ovulation, the clitoris was relocated from its ancestral position inside the copulatory canal. This anatomical change made it less likely that the clitoris receives adequate stimulation during intercourse to lead to orgasm.
“Homologous traits in different species are often difficult to identify, as they can change substantially in the course of evolution, ” said Pavlicev. “We think the hormonal surge characterizes a trait that we know as female orgasm in humans. This insight enabled us to trace the evolution of the trait across species.”
Such evolutionary changes are known to produce new functions, as is well established for feathers, hair, or swim bladders, etc., which originated for one purpose and were coopted into secondary functions later.