Susan Moller Okin’s critique of libertarianism in Justice, Gender, and the Family has received only slight attention in the libertarian literature. I find this neglect of Okin’s argument surprising: The argument is straightforward and, if sound, it establishes a devastating conflict between the core libertarian notions of self-ownership and the acquisition of property through labour. In this paper, I first present a reconstruction of Okin’s argument. In brief, she points out that mothers make children through their labour; thus it would seem that mothers own their (adult) children; but this implies that the children are not self-owners. I then examine the two most common objections to this argument in the literature: mothers do not make children, and acquisition by labour includes an exception for persons. I give several replies to each objection, including an extension of Okin’s argument that I call Okin’s dilemma. This dilemma argues that the libertarian can avoid Okin’s conclusion only by requiring an involuntary property transfer. And this alternative, it seems, is just as unacceptable for many libertarians. I close with some speculation about the further implications of Okin’s dilemma for libertarianism.