While its function has left biologists baffled “for centuries,” researchers from Yale University and the Center for Prevention of Preterm Birth at Cincinnati Children’s Hospital, now believe that our female ancestors only released an egg after achieving an orgasm, which is still the case for other mammals, including cats, rabbits and camels.

Mihaela Pavličev, co-author of the study published in the JEZ-Molecular and Developmental Evolution journal, says it’s “important to stress that it didn’t look like the human female orgasm looks like now” and that it was “maybe modified further in humans.”