The idea is simple:

  • Pick a target fertility rate, e.g. 2 to maintain steady population.
  • The first 2 biological children of each man get generous child subsidies
  • 3rd, 4th etc children from the same father get no extra subsidies
  • To avoid incentivizing rape and teenage pregnancy, no subsidies for children conceived by rape or by a parent under 18 at time of conception. EDIT I've been told this "punishes women for being raped" so instead I will say no subsidies only if the dad was raped or underage.

Since this makes men a bottleneck on reproduction just like women, it will completely smash the gender roles people hate. Men won't be able to run around and impregnate 10 women and have the taxpayer pick up the bill for all of them. Smart men will be just as picky about who they have sex and kids with as women are. Women will be encouraged to be more forward if they want to nab a good father for their kids.

Q: why not also limit benefits to two per mom?
A: Her body her choice, if some women don't want to get pregnant while others want to have 5 kids with generous subsidies, it doesn't matter so long as we subsidize the target fertility overall.