I have to go in a couple minutes, but for now let me just say that in the developed world we are rapidly approaching the juncture where the rubric of 'population growth = economic growth' will become obsolete, and once we get there nothing will be the same ever again. :)
Of course there's another layer of social problem that will come then. What happens when so much of our labor is automated and roboticized that, from an economic perspective, we don't need the majority of people? When we're able to produce everything we need and then some with only 10 or 20% of the population actually doing something that even vaguely relates to productivity what are we going to do with the other 80% of the population? If you ever read and Judge Dredd that's an on going theme, education is primarily focused on teaching kids hobbies because they'll probably never have a job of any kind, and of course crime is rampant because the general population is pretty much bored to tears. It's probably a recipe to total socialism when you really think about it, once we no longer need people to be productive, once we no longer even have the ability for most people to be productive, we're going to have to find a way for people to get food and shelter that doesn't involve any sort of labor. It'll be a wierd world.