This ain't gonna happen, due to hypocrisy and political correctness.
99% of people playing this game had, are going to have or are having sex right now, and I don't care what you people say - it is a good thing.
99% of people playing this game are NOT murderers, thief, gang members, drug or alcohol abusers, slavers or suicide bombers, and that two is a good thing.
In the game world it's totally opposite, so it looks like killing, stealing, using drugs, enslaving people and suicide bombing is a-ok, fine_by_me, I_don't_mind_if_you_don't_mind, but sex and nudity is bad, wrong and evil (I'll get back to nudity once the 3d era stars and somebody -like me- will make a nude patch). That's silly.
...anyway, this ain't gonna happen, but one can still imagine how it could work.
A consensual intercourse could give some sort of bonus, like an extra action point (or two if someone has the Kamasutra perk). It would last for say (CHA/2)x6 real life minutes, in a rape situation the duration would be cut in half. The bonus would kick in 5 minutes after and only if both participants are still alive... Why so? Today's leisure time activity is finding someone weaker, killing him or her and looting the body and I really would hate to see it change to raping then killing and looting.
And there's all the little bits alike sex addiction, condoms (maybe you could craft them?), NPC prostitutes, and the Golden Globes porn holodisc productions.
Could be fun, but well... ain't gonna happen.
