ABSTRACT
What has come to be known as the non-identity problem1 raises some puzzling questions about the relationship between the well-being of others and our reasons for action. The non-identity problem arises in what I will call a non-identity case: a case in which an action that is the condition of an individual’s worthwhile existence also imposes certain constraints on the individual’s prospects for well-being.2 For example, consider a case in which some prospective parents use in vitro fertilization and select an embryo for implantation on the basis of a gene that will result in a particular disease. If the resultant child has a life worth living, then she is made no worse off in any respect by her parents’ action of selecting for disease than she would have been, had they not performed that action. After all, if they had not selected for disease, the embryo with the gene for the disease would have been discarded, and the resultant child would not have existed: she is non-identical to anyone who would have existed, had her parents not acted as they did. Nevertheless, many people have the intuition that there is a moral reason against the kind of action that the parents performed. A solution to the non-identity problem must either justify the intuition that there is a moral reason against the very action that brings someone into existence in a non-identity case or explain that intuition away.
