An increase in income is generally tied to having less children, not more. I read a study (which I can't find right now) that studied the effect of policies tha

An increase in income is generally tied to having less children, not more. I read a study (which I can't find right now) that studied the effect of policies that gave income based on the amount of children, and there is no increase on the amount of children people have. Argentina, for instance, has a program called Asignación Universal Por Hijo that (roughly) pays you for each child you have, provided he goes to school.