Men think more about sex because women actually do have sex all the time
women don't value the sex as much as guys since they don't have to work for it. heck they get paid for it in many ways.
Girls at 13 are already having boyfriends and many of them are tired of sex by the age of 15. boys are still interested in playstation and sports until late teens...heck many guys start having sex after 20's.
It's hypocrisy at best...just like when a MARRIED evangelist who's having sex every day preaches to kids to stay as virgins forever
In the end it's women's lives that revolve much more about sex and relationships.