Yes, of course that's what I think
Don't be a presumptious twat, I didn't say that. It just appears that most girls with "standards" don't walk around half naked on a night out.
The evolution argument goes like this: Men can reproduce as many times as they like (within reason). One fertile man can make a few women pregnant per day if he wishes (assuming the women are happy with this). But it's physically impossible for a woman to get pregnant and reproduce more often than once every nine months. Her eggs are more precious than the man's sperm - she doesn't produce as many. Also, she has to nurture the foetus and presumably look after the baby once it pops out. Therefore, she is more fussy about choosing someone who is going to be a good father and provider, or who has good genes to pass on.
Of course, this is a hugely generalised account of the whole thing. I don't believe we consciously look for someone with good genes, but it does explain why the majority of women don't like the idea of promiscuity as much as the majority of men. There is also the nature / nurture debate (conditioning) - are women just less promiscuous because it's less acceptable? I think it's a bit of both, like most of these things.
The danger with the evolution explanation is that it gives people an excuse to have a go at any woman who has consensual sex with someone she hardly knows, whereas men get away with it all the time because they have to "sow their seeds".
It's all about evolution and conditioning.
I don't believe we consciously look for someone with good genes, but it does explain why the majority of women don't like the idea of promiscuity as much as the majority of men.
This is all according to this chemical Review magazine we get at school.