I keep hearing men, inspired by the desire for egalitarianism, complain how this is unfair. But it's like that for a reason, and it's not going to change. The reason is that male sexuality is indiscriminate, and female sexualiry is hyper-discriminate. It's not only because women don't want to deal with rejection (although that's part of the reason), but it's also because women need to erect barriers in order to make men prove themselves. In the absence of these barriers, it's very hard for a woman to tell if a guy really likes her. And, unless she wants to just fuck lots of random men, she will get used for sex. Because men will fuck anything. However if there are barriers to entry: approach first, take all the intiative in the beginning, pay for the first date etc. then this will typically filter out men who just want an easy lay. It's not 100% proof but it's as close as you're going to get.