Social engineering via tax codes is ALWAYS bad and ALWAYS antithetical to freedom. Just slash the tax rates, period, and let people make their own choices about what to do with their own money. Many of them will have more children, but others won’t. That’s called freedom.
And the budget cuts to compensate for the initial drop in tax revenue from slashed rates need to hit the generation that’s responsible for this mess, namely those now hitting retirement age, who presided over a massive expansion of socialist welfare programs because they wanted hand-outs for themselves.