Our current child support system incentivizes people who are unsuccessful at life to have children while penalizing those who are successful. Child support is currently based on income- the more you make the more you pay.
I suggest changing that to a fixed monthly fee- $1,200 a month no matter who you are.
This will encourage natural selection by codifying it. The most successful people will be able to easily afford having the most children.
Another effect is that it will reduce a big problem America has- poor unwed mothers. Poor men will have Uncle Sam enforce shotgun weddings. Beautiful.