As with most issues, people embrace coercion when they shouldn't, and don't need to.  You can persuade justly when force would be criminal. Societies should incentivize the highest IQ to have multiple children.  The lowest IQ to have no children.  Perhaps 84-99 IQ to have no more than one.  etc.. Free societies have natural, organic, eugenics.  Forced redistribution of wealth is sabotage, and dysgenics.