At the moment we’re mainly debating slaps on the ass, where no chance of pregnancy is involved. But regardless, at the risk of being highly offensive to humans who think themselves to be so far above the “beasts”, let’s compare the sexual habits of our nearest relatives for a minute. Female bonobos are notoriously promiscuous. Bonobo society is in fact constructed around this very trait. And it works great for the bonobos. Yes, they are still choosy (they don’t mate with the genetically unfit, for example), but among the genetically fit (which is the majority of males) they make little distinction. Regardless, they are not terrified of their male brethren and don’t feel violated or threaten when one approaches with interest.

Chimps are similar but different. Female chimps are “protected” by the Alpha Male. It’s really only the terrorising by the Alpha male that keeps the female “chaste”. But when a suitablably healthy would-be usurper to the alpha male makes sneaks through unobserved by the Alpha, the female usually doesn’t hesitate to offer up their rump for his and her enjoyment. Regardless, female chimps don’t fear the the sexual interest of their male bretheren and seem to feel “violated” or threatened when one displays that interest physically.

I invite you to read the book “Sex at Dawn” for much, much more on this subject. It makes a very compelling case (from studies of male and female anatomy and social behaviors) that female humans have been evolutionarily programmed to be relatively promiscuous—less so than bonobos but far more so than chimps.

In sort, there’s tons of evidence that human females are naturally promiscuous. Virtually all biologists of every flavor, and also evolutioanry psychologists, agree with this. By contrast there’s little to no evidence that they are innately chaste.