While I agree with your later point about having larger families leading to a healthier mix of time spent, I cant agree with your first point.

Yes, most parents talk a lot about their kids and that can be annoying if you don't have kids. Most single people are just as annoying though. You can talk about your kids or you can talk about your vacation, or your job... for the most part people will find it interesting if they relate and boring if they don't. I don't think there's a qualitative difference there between parents and single people, just different audiences that will be receptive to what they're talking about.