I am against forced sterilization (this would be a violation of the basic right of physical integrity). This does not contradict that it would perhaps not a bad idea to give a financial incentive for sterilization (though I have to think more about the best way of implementing this).

Nevertheless I see the much larger problem in the fact that many pairs choose to bring children to the world because this is the action that is encouraged in society (most people are simply conformists). If we could make it the default that it is frowned upon if a couple, for which it will be rather likely "from available data" that the children will be in a bad position in future society, nevertheless decides to have some, I think a large part of the problem would be solved.

I also would encourage children from the bottom quantiles of intelligence or earnings to say clear words to their parents that they are part of their problem.