Actually I think there are a lot of social issues with kids in video games. To be honest I think Linden Labs had sort of the right idea when they created a kiddie version of Second Life to keep kids away from the adult content and stuff (allegedly). I think there should be some kind of age filter on XBL and World Of Warcraft, pretty much making kids play with other kids on their own servers, and then having adult only servers.
My problem with kids has mostly been with fighting games however, and people reporting you for "poor sportsmanship" when you beat them, along with the general insults and "trash talking". Truthfully I think one of the problems with general access voicechat via things like XBL is that trash talking has gotten out of control. I've kind of felt that it was no big deal to begin with, but as time has gone on, it seems like it's become more of a chance to be hateful from the protection of a computer. There is nothing good natured about it, since your not likely to run into the same person again due to the sheer number of players. I suppose this isn't age specific, but a lot of it is.
I also feel that kids are incapable of the responsibilities inherant in adult level gaming. Oh sure, there have been plenty of kids playing WoW who are just fine. BUT given the realities of Homework, needing to go eat dinner with the family, and similar things I've oftentimes felt they really don't have any business being involved in WoW endgames.
See, it's a problem when your half thinking you should chew out parents about teaching their kids responsibility, because they call the kid away from the computer (leaving a bunch of people waiting, sometimes as many as 39 of them in old scholl WoW). On one level I think some things are more important than gaming, on the other it's still pretty F@cked up, and truth is I don't think a kid should be in an enviroment where they can make a committment that their age very well means they can't keep.
There have been a few situations when I've seriously wanted to throttle "mom and dad" or say something really nasty one way or another. The fact that I'm not exactly "right" there on many levels sort of illustrates the problem.
So basically when it comes to gaming over the internets, I think kids need to basically be relegated to their own servers and subsystems.