Natural selection, it seems, often smiles on strumpets. Sorry, boys. - Olivia Judson

If a proclivity for promiscuity is genetic, then yes, promiscuous behavior will become more common if loose females tend to have more children than their monogamous peers. That’s how natural selection works.

I’m afraid that females in many species often provoke males into fighting over them. When the mood strikes, they make themselves conspicuous—then stand back and watch the battle, before mating with the winner.

Evolution does not obey human notions of morality, nor is human morality a reflection of some natural law. The deadly sins would be different if they mirrored evolutionary no-no’s. Lust, for one, would be deemed a virtue; chastity would be deplored.