I was wondering about this topic not long ago as well and came across this article: http://dieoff.com/page99.htm (not sure if that's the original link I saw but it is the same paper).

Basically it's about there being a curve for population size vs standard of living. We can't control the size of the population for the entire world, but a country can for themselves.

I don't really have much of an opinion on it, and can't say whether the article is bunk, but I did find it an interesting read.