Considering that it’s happening all the time, everywhere, all across the world, there’s a lot that scientists still don’t know about the female orgasm. Although the debate over the chemistry of female ejaculation has been settled, it’s still not definitively clear how many types of female orgasms there are.
The most tantalizing question of all, though, has barely been addressed – namely, what is the evolutionary point of the female orgasm? Writing in the Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, a team of scientists at Yale University thinks they’ve come up with an answer.
Rather than merely evolving as a trait to accompany the male orgasm, which some presumed was an adaptation to encourage pair-bonding between partners, these researchers have concluded that it was once the key biological trigger required for ovulation to take place.
When women orgasm, they release two hormones, oxytocin, and prolactin. In the females of wild placental mammals, this type of hormonal discharge actively causes ovulation to begin, and without it, pregnancy would not be possible. The male and female orgasms work together, so to speak, to begin ovulation.
It’s likely that the same mechanism initially evolved in human females for precisely the same reason. Over time, women developed the ability to ovulate on cycles independent of male sexual activity. This hormonal function was rendered unnecessary and it became superfluous, but it stuck around in female biology due to its secondary role as a pleasurable bonding mechanism.
“Prior studies have tended to focus on evidence from human biology and the modification of a trait, rather than its evolutionary origin,” co-author Gunter Wagner, a professor of ecology and evolutionary biology at Yale University, said in a statement.
Indeed, earlier studies have pointed out that the fertility of female partners does not seem to depend on sexual activity. From this logic, it was concluded that the female orgasm never had a direct role to play in reproductive success. So, contrary to what reams of researchers have previously claimed, this study suggests that the female orgasm evolved to aid reproduction in conjunction with the male orgasm – biological partners in the circle of life.
The male orgasm has a clear purpose when looked at through the lens of natural selection. It seems likely that this moment of fluid-based frivolity is designed to encourage male creatures, including humans, to spread their genetics around by impregnating as many females as possible. Having sex and making babies is the underlying function of “gene machines” – animals of all shapes and forms.
However, the driving forces behind the evolution of the female orgasm are far less clear. Many have thought that it evolved as an incidental by-product to the male orgasm, whereas others hypothesize that it encourages the male to bond with the female, ensuring her genes also get passed down the generations. Some have wondered if the rhythmic pulsations that occur during the female orgasm help to vacuum up the sperm into the uterus.
This study, taking a relatively novel comparative biology approach, suggests that the secret of the evolutionary origins of the female orgasm has been betrayed by the relic hormonal discharge that accompanies it. Over time, this hormonal discharge became inessential for human survival through reproduction, but it still occurs nevertheless.
Of course, just because it no longer has a reproductively “useful” role, it doesn’t mean that the female orgasm is useless – far from it. Sex is meant to be enjoyed, first and foremost, and surely, that’s its primary function in the 21st century.