Good question, KellyChandler. No, I don't think MITM is just for kids at all. In fact, I think that most of the subjects they deal with are geared more toward late teens/adults than kids. A few examples that I can think of right of the bat:
-How many times has the topic of sex come up between Hal and Lois?
-In the pilot episode, Lois is topless for nearly 10 minutes! That's definitely not kid's material!
-The boys use bad language throughout the series, even when they were only 10 and 12 years old--while it's nothing that bad, it isn't really too appropriate for kids.
-In the episodes Stupid Girl and Thanksgiving, the subject of underaged drinking comes up. In No Motorcycles and A.A. the subject of alcoholism is explored.
-Francis smokes underaged (specifically in the Pilot episode, but in many other episodes from the first 2 seasons too.) Dewey smokes underaged in Reese vs Stevie.
-The topic of sex has come up quite a bit, especially in this season. This is obviously because the boys are growing up, but if they intended it to be a kid's show they could avoid these more adult plotlines. In fact, nearly 1/4 of the episodes from this season have dealt with sex in one way or another. The episodes that come to mind are Burning Man, Jessica Stays Over, Blackout, Army Buddy and College Recruiters.
That's all I can think of for now, but I'm sure there's a lot more. So no, I would say that it is not a kids show at all.
BTW, in the future, please keep your posts left-aligned. It's really hard to read them when you center and italisize everything.