[beerlord]

Overpopulation. Too many people, not enough resources to support them. 600m Indians without proper access to water. Better access to contraception and changing social attitudes needed - the expectation that if you are impoverished you should have no children and save your money to improve your wellbeing, for example.

[raincom]

Empirically speaking, poor people (and the super wealthy) have more kids than the middle class do.