Something I've read about is that young people going to school (ages 10-20) are likely to find partners. However, they won't move out of their house (=won't have kids) unless the house is closer to school for BOTH of them.

Not sure how true that is anymore, but it seems to be the case with my guys (built a school in a central location, houses on the outskirts, no one's reproducing until they're 30ish -.-)