This is actually a classic ancap take: https://en.wikipedia.org/wiki/Murray_Rothbard#Children's_rights_and_parental_obligations

He argued that parents have the right to put a child out for adoption or sell the rights to the child in a voluntary contract in what Rothbard suggests will be a "flourishing free market in children". He believes that selling children as consumer goods in accord with market forces—while "superficially monstrous"—will benefit "everyone" involved in the market: "the natural parents, the children, and the foster parents purchasing".[151][152]

In Rothbard's view of parenthood, "the parent should not have a legal obligation to feed, clothe, or educate his children, since such obligations would entail positive acts coerced upon the parent and depriving the parent of his rights".[151] Thus, Rothbard stated that parents should have the legal right to let any infant die by starvation and should be free to engage in other forms of child neglect. However, according to Rothbard, "the purely free society will have a flourishing free market in children". In a fully libertarian society, he wrote, "the existence of a free baby market will bring such 'neglect' down to a minimum".[151]