A lot of families around the world aren't able to have the number of children they'd prefer to have. There's a lot of reasons for it many of which come down to people not having enough money for a family. Lack of affordable housing and childcare are big ones. Uncertainty about the security of our future is another. If a government did want to prevent humans from reproducing, they've got a pretty good head start and plenty of examples of what to do more of.