This is an outstanding question. I had to address this on the death of a much loved mother and the apportionment of "things" that her children had to divide on her death. She lived well and loved things very much. Absolutely no benefit in accounting was made for bringing and giving her grandchildren. So the child who gave her less in things but the most in grandchildren received back the lessor of things about ten times less.
So the childfree children were heartely penalized as their contribution to their mother was mainly in things.
Alas the childfree children were penalized by the ten things they got from their inheritance. For in each thing was a memory of her death. And the child who gave less things but the most children rejoiced in the children that reminded him of her life.
The penalty of a childfree life is the lack of living that children provide. Do not get me wrong here for I am adopted. So I do not address "birthing" as much as raising children which if so chosen even the "child-free" can do.But those who wish and are free of children are bound in the chains of things. And that will always be more than ten penalties. For to be free of children is to deny our connection from where we came. The penalties are self inflicted. The notion of ""child" -"free" could only come from those who see children as bondage.and that is penalty enough.
If there are other penalties we as a culture should be ashamed. For those who are not involved with the bringing up of children in some form are worthy of our sympathy and not penalty.