Regardless of it's historical underpinnings, sex in modern human societies has become more recreational in nature, than procreational. Sex seems to me to have transended procreation. 'Tis like going fishing ... for food or ... for fun. No one wants to go fishing with just anyone, and there are certainly easier and more efficient ways today to obtain a fish dinner than to sit on the banks of a beautiful river. I have it ... the primary current evolutionary purpose of sex today is to inspire new expressions of art. Well that, ... and vice versa.