The human body is a mysterious li'l organism. Why do men have nipples? What's the deal with pinky toes? And — given that it doesn't appear to serve any specific biological purpose — why does the female orgasm exist, anyway?
Researchers may be one step closer to figuring out that last one.
In a new study published in the journal JEZ-Molecular and Developmental Evolution, scientists at Yale University and the Cincinnati Children's Hospital have determined that "female orgasm seems to be a happy afterthought of our evolutionary past when it helped stimulate ovulation."
Ah — so it was once important AF for the reproduction of our species. That's interesting!
The researchers didn't reach their conclusion by studying the biology of actual human women. Instead, they focused on "other placental mammals" (i.e. mammals that exchange nutrients with their fetuses via the placenta) to see if they could identify clues about how the female orgasm functioned in our species way back when, before we all evolved into smartphone-wielding bipeds.
Researchers noticed a discharge of the post-orgasm hormones prolactin and oxytocin induced ovulation — a key part of the menstrual cycle that allows eggs to become fertilized — for the mammals in the study. Oxytocin is already known to play a role in bonding.
"We think the hormonal surge characterizes a trait that we know as female orgasm in humans," researcher Mihaela Pavlicev said in a press release. "This insight enabled us to trace the evolution of the trait across species."
(The press release is unclear on which mammals were used in the study, as well as why researchers think humans eventually evolved away from needing post-orgasm hormones to spur ovulation in the first place; Mic has reached out for comment and will update if we hear back.)
Past theories for the possible reasons behind the female orgasm have said it helps couples bond closely and thereby "facilitate and sustain the long-term pair bond at the heart of the nuclear family," while others have always just written it off as an "evolutionary accident." This new theory seems to echo both, but takes things to a whole new level by suggesting that orgasms were once a key ingredient in conception.
Imagine that! A world in which female orgasms were required in order to reproduce. Anybody have a time machine?