Female orgasm could have originated from reflex triggering ovulation, study suggests

Scientists have spent years trying to see if the female orgasm serves a purpose beyond sexual pleasure, given that, unlike the male orgasm, it has nothing to do with reproduction.

According to a new study involving rabbits, it could indeed have a biological function: ovulation.

The research, published in the journal Proceedings of the National Academy of Sciences, supports the idea that female orgasms might have originated from a reflex that prompts some female mammals to release eggs during intercourse.

Researchers conducted the study by analysing the number of eggs released by 21 rabbits after they’d had sex with a male rabbit named Frank.

Some of the rabbits were put on antidepressants known to reduce the capacity for female orgasms, while others were not.

The scientists found that the rabbits who were given antidepressants, and therefore would have had fewer orgasms or none at all, released 30 per cent fewer eggs compared to the rabbits that were not.

The findings fit the authors’ theory that rabbits need to orgasm in order to ovulate, something that similar studies have also suggested in other mammals.

In 2016, the same team looked at 41 different species of mammal, including camels, cats and koalas, and found that 15 of them also had the same reflex, whereby ovulation is triggered by copulation.

Of course, the same effect is no longer true for humans as they ovulate spontaneously. But the researchers think that it could have been true for our mammalian ancestors.

Explaining the significance of their new study, the authors write: “The existence of female orgasm is intriguing for two reasons: On the one hand, female orgasm is not necessary for female reproductive success, and on the other hand, this neuro-endocrine reflex is too complex to be an evolutionary accident. This led to many proposed evolutionary explanations, most of which have little empirical support.”

Citing their 2016 study, the authors said they previously suggested that female orgasm “uses a mechanism that originated for inducing ovulation during copulation”, which it says is a:mechanism that still exists in many animals but lost its role in others.

“Here we provide experimental evidence, strengthening the likelihood that female orgasm evolved from copulation-induced ovulation,” the authors continue.

“This finding helps interpreting otherwise difficult to explain aspects of female sexuality, such as the low rate of female orgasm during intercourse.”

However, co-author Dr Mihaela Pavlicev of the University of Cincinnati says further experiments with other animals will be different in order to ascertain why the female orgasm has remained in humans, but the ovulation reflex has not.