Children are peculiar persons: In many ways, they are "works in progress." Also peculiar is our treatment of them: We treat children in ways that it would be clearly immoral to treat other persons; most significantly, we give parents authority over them. Presumably the peculiarity of children as persons explains and justifies our peculiar treatment of them. But how exactly does this explanation and justification go? Some point to the child’s lack of fully developed cognitive abilities as the ground for parental authority. While I do not deny that this is part of the story, I think that other, more important factors are also important. In particular, I suggest that parental authority is justified because of the fact that children have not yet fully developed their own capacity for moral agency. I discuss three components of moral agency that are not fully developed in children. One is temporal extension, the ability to identify and plan for one’s own future. The second is the capacity for a conception of the good. The third is the ability to act on norms of moral decency. I explore the various ways that the parent can be seen as a sort of moral interface between the child who has not yet fully developed moral agency on the one hand, and the community that is made up of fully developed moral agents on the other. I suggest that much of the moral role of parent can be best understood in terms of this kind of interface.