I would lower it to 14 or 15 (at least for men, who can't get pregnant, and are not forced into sex-slavery)- the age (according to that unimpeachable source, Wikipedia) in the more advanced countries in Europe. Germany and Austria -14; France, Sweden and Denmark -15. Although I don't have any interest in guys that young, it seems really cruel and stupid to imprison some guy for years because he had sex with someone only a few years younger. (The 18 year old and the 14 year old boyfriend). I know a number of guys who related that they started having sex when they were 14 or so, and they turned out just fine - in fact they were the ones initiating the sex (which is typically the case). Looking back, I certainly wish I had started having sex at that age. (My parents would not have approved.) In the USA today, kids are experimenting with sex at much younger ages than when I was a teenager - all the high school pregnancies aren't the product of phlogiston.