I went to see Quantum of Solace in Royal Plaza two weeks ago, and there were 5-6 year olds with their nannies in there. So no, I don't think it's a problem. People don't seem to mind about ratings, if there are any in Qatar at all... :p
Go take your family to the movies and enjoy together! :)

I want to mention though...I'm surprised by everyone's complaints about the noise/distraction level in cinemas here. In my experience the audiences have been fine. The only unforgivable distraction is ringing mobiles--but so far that's the worst of it.
Or maybe I'm just lucky! :)