The notion of sex being special is also very much attributed to gender roles and the given conception society happens to have on it.

It is pretty close to a human universal that females are choosier about their partners, and there's a good evo psych explanation to go with it. Have their ever been societies where lots of women are completely fine with prostitution -- maybe so fine with it that the bottom drops out of the market?

But if we start imagining how society could be different, let's go with one where sex really isn't special. If someone asks you for sex, it's rude not to have sex with them, just as today it's rude not to say "hello" when someone greets you. No need for a private place, just do it wherever you are. And why not the little kids too? Somehow I don't think this is a very appealing society to girl lovers, to see your special little girlfriend giving or getting oral with anyone who asks. Maybe for some it would be appealing.

It seems to me that most girl-lovers want sex to still be special, they just want it to include man-girl sex. They imagine changing society in a way which just happens to fit neatly with their desires. I'm not saying it's impossible -- Heaven's Gate was possible -- but I think it goes against the grain of human nature.

In any case, the subject is far more loaded than swimming.