Consider that the inventor of the free individual tied to his fellow individuals only on the basis of contract and consent, John Locke, drew a line at raising children. Husband and wife can relate to each other as free individuals unsuckered by love, but not parent and child. Parenthood, according to Locke, has nothing necessarily to do with biology, but is a set of rights and duties possessed by whoever cares for a child. That indispensable care or love is not a characteristic of a free individual. Caregiving is at the expense of any particular individual’s productivity, as well as time-sucking constraint on his or her freedom. The classes of parent and child have to be recognized and facilitated by law, although conceivably even the categories of husband and wife might wither away in pursuit of happiness or maximum possible liberation. The libertarian utopias that imagine otherwise are pretty much always childless. And unless the transhumanist’s Singularity actually comes, how realistic is that?