Population Control

At the rate the numbers are growing, nothing short of a massive world war/genocide would lower the population, and that is clearly not the answer. IIRC poorer parts of the world actually have more children because they are afraid not all of them will be successful, so more children = higher chance of successful offspring, meaning their legacy/family line will continue on. I think if we can raise the general wealth level of the poorer countries they will have a normal number of children, not this 5-8 children nonsense. Exceptions would be those who give birth to an absurd amount of children at once (read: triplets and the like). I've always heard and read of poor families giving birth to tons of children. I wonder why?