Is casual sex morally acceptable? Historically, people have viewed sex as a serious matter that should be restricted. And social conventions have typically told us to withhold sex and control our human lusts.
Most religions therefore consider promiscuity a sin; something immoral that was even punished by death in the Middle Ages. The sanctions for promiscuity have become way lighter since then, and in the modern day West, the sanctions have for the most part become only of a social matter: judging, exclusion, and shame.
Though I’ve covered it in some of my previous articles (like this one or this one), in a nutshell, female sexuality has been restricted in order to create order and avoid chaos. Remember, the majority of males out there compete over the provider role, and therefore are not very sexually attractive to women in comparison to the small minority of lovers – those men whom women find sexually attractive and who provide them sexual satisfaction.