Poor women already have the most kids while the highest income bracket has the most abortions. It's not a matter of financial incentives.

I don't think that follows. Higher income brackets may just have more to lose from having children (i.e., careers, vacations in Europe, college funds, higher investment in offspring) and have a better ability to prevent having children.

It's true that it's not only a matter of financial incentives. But it's certainly that.

Spez: The NSDAP did have an effective program of giving newly weds a decent sized loan and 25% was forgiven for every child.

It's worth trying.