So we’ve discussed overpopulation, but what about the opposite? There is evidence that as nations become more advanced, people prefer to have fewer kids, or to not have kids at all. And once people stop having kids?

Note: if you think this sounds ridiculous, you are obviously not Japanese. The government there has been banging its head against the wall trying to figure out how to get its young people to start dating. If they fail, Japan is headed for a demographic crisis (and Europe is nipping at its heels).