very simple prove, go outside and ask the first girl you see if she wants to have sex, she's going to probably say no. But for guys you don't even need to go outside, wake him up from bed while sleeping and ask him to have sex and he will probably say yes if she is hot. Women enjoy sex just as much as men but they are more reserved and "classy" about it, again another result of sociological norm; no woman wants to be a slut and all women think their current relationship should be the best ever.
I would disagree with you there...
I desire sex but I would not agree to having sex just with some girl who would come up to me and ask for it.