If wacky is the order of the day, how’s this for a sci-fi population control plan:

Devise a form of birth control that can be put into the population’s food or water supply. Make the antidote readily and freely available but require both partners to take it for a couple of weeks before they can conceive.

This results in huge reduction in unplanned pregnancies, greatly reducing the birth rate. It would also nearly eliminate the need for abortions which is not a bad thing either.

anyway. I dabble in writing SF. That’s the most effective population control plan I’ve been able to come up with that still allows people to freely reproduce at will. It’s not without its totalitarian aspects still but in a crisis scenario it might be a way to go.