I think that someone gets an overall tax rebate when they have children is a reasonable decision for a society to make.

But the real problem here is that there are a ton of adults who would love to have kids but are medically not able to for a bunch of reasons, from autoimmune disease to genetic differences to the simple fact that young people get cancer too and infertility because of treatment or the illness is a thing too.

Is it really wise for a society to treat them as if they willingly deny the society additional benefactors and valuable younger members?

It feels wrong for me that you get treated unequally by the law because of circumstances that are not choice-based and your decision to make in the first place.