If you really want to get rid of high birthrates, there is a simple, sure-fire solution which wouldn't infringe on people's rights of having children.
End welfare.
It is a worldwide metric that those in lower income brackets have more kids. Its this way in America to Africa. When the poor are subsidized, they continue to have babies and grow the population. Likewise, in countries with less poverty, you generally find lower birth rates.
When you end welfare and government subsidies, you have 2 responses from those that have tons of kids: Either they will have less, as there are fewer incentives in social democracies to have children, or in very poor countries, they will have to either have fewer mouths' to feed, or simply go the way of Darwin and die. Its very harsh, but would fix our overpopulation problems, as you usually see overpopulation in very poor countries.
Back from the dead, I'm afraid.
