Abstract
In this paper I develop a theory of the acquisition of parental rights. According to this investment theory, parental rights are generated by the performance of parental work. Thus, those who successfully parent a child have the right to continue to do so, and to exclude others from so doing. The account derives from a more general principle of desert that applies outside the domain of parenthood. It also has some interesting implications for the attribution of moral parenthood. In particular, it implies that genetic relationships per se are irrelevant to parental rights and that it is possible to have more than two moral parents