So, it turns out that the ebbs and flows of a cisgender woman's sex drive aren't as simple as evolution would predict. Of course, Millheiser would be remiss not to add that many women see a noticeable increase in their sexual drive during ovulation week three in a four-week cycle , which can be explained by that aforementioned nagging evolutionary drive to procreate. It's in your interest to be horny from your body's perspective since one of our jobs evolutionarily is to procreate. I'd have my usual PMS symptoms, where even the thought of sex would make me nauseous. OK, so this isn't a concrete scientific fact -- the theory is still debated -- but if you've ever lived in a dorm or had female roommates, it doesn't feel like a coincidence that you're all reaching for tampons at the same time. Sure, you might have cramps and feel bloated. Third, there is the hormone shift. Advertisement No matter the reason, there are some clear benefits to having period sex. Question says it all, indeed.