I assume if it reaches dire levels the government will just mandate that you raise children. I dont see anything wrong with that, personally. Raising kids is a duty like paying taxes or registering for the draft. Previously, it was just assumed that people would do it on their own, but it seems like the government needs to add "sticks" to get people to do it.
This is such a cool topic. Homo sapiens are exactly evolved to reproduce. This is instruction #1, or else we wouldn't be here to discuss it. We might call this the super-not-weak anthropic principle?
We produce multiple hormones which control our behavior to reproduce, and then different ones to raise those kids. It's been nice for millions of years. Parents think that creating their children is the best thing they ever did, generally speaking.
Yet... we have recently created what is otherwise a really cool economic system, which somehow overrides all of that!
Aside from "are we alone in the universe," this is one of the most interesting problems in my mind.