Are unenforceable moral requirements possible? It is normally true of moral requirements that transgressions will create in some other person a grievance. If, without excuse or justification, I break your nose, steal your bicycle, falsely slander your name, or fail to repay your loan to me, you have, at the least, a right to complain, a claim to some sort of correction, and perhaps a right to prevent further transgressions. These rights are personal to you; they may not be asserted by just anyone. But, as has long been known, some moral requirements do not entail correlative individual rights of rectification. Mill, for example, noted the currency of the terms “perfect” and “imperfect” to distinguish between duties that do and duties that do not entail a correlative individual right to compel performance.1 More recently, Derek Parfit has given a vivid example of a wrong giving rise to no grievance. A couple know that if they have a child now there is a risk that it will have a defect, but that the risk will pass if they wait. The couple decide to have a child now rather than wait, or are careless and then decide not to induce an abortion. The child is born with a handicap that a later-born child would not have had; but of course the child that is born would not exist at all had its parents followed advice and waited. So long as the child's life is at least barely worth living, the child has no grievance against its parents for their conduct, nor has anyone else. Even so, the parents have acted not merely badly, but wrongly.