I am sat here thinking of new game styles as i am bored of fps etc and came up with this idea of a 3d world where you have to reproduce and make a family , like there would be men and women character models and if you fancy someone etc , you get to have sex with them and make a child.Then you would have to bring up the child in the 3d world protecting , feeding , loving it, your going to see it grow realtime but there could be things like thiefs trying to steal your food and belongings which would be other players connected to the server..., basically just like in the old days of life where you had to go out and fight for food like kill animals and cook them and try bring up a family at the same time and like after 9 months she gives birth to your child , then after 3 or 4 years it will able to take its first steps (just like in real life)

Like most good game ideas, it's already been done before to some degree :D The Guild has all of these features, albeit in singleplayer only (but on the other hand, it's fun). I haven't played The Sims but I imagine that a lot of those features show up in there, too.

If I were to play this real-time and online though, it would be too much like Real Life. I'm not sure if that's a lot of fun. If I'm gonna commit three years to raising a kid, I might prefer to do it IRL.

This is a core feature to the multiplayer RPG I am developing, though offspring go into hidden 'incubation' until they are considered to be the age of majority (primary reason being I don't condone violence against children -- or its representation in any medium -- coupled with the likelihood that I don't want to see players resort to this for whatever "strategic" reasons).

It's a good mechanic, and handled responsibly, can lead to dimensions not really explored in games (e.g. "real" clans of players, generations old).

Fairy Tale Online you have to wait to be born to a pair of players in game to play, entirely player driven with their own societies and cultures, quite interesting. There's an interview on Tigsource with its creator Casey Flynn.