I was once given a not very convincing argument by a bible waving relation about why there, in fact, was no population problem. Mind you, it did come from his church in GA.
It goes like this...
If each married couple only has one child then the population will actually shrink, so every couple should have at least TWO kids.
Additionally, because some couples has no kids or only one, then others can have three or four. Come on he said, do the math.
Trying to explain life expectancy expansion, the fact that his kids, him and his siblings, his parents and thier siblings, grandparents etc etc where also living didn't seem to phase him.
Oh well...