Identity and disability

There are various methods of avoiding giving birth to a disabled child. Many have the result that people who would otherwise be born are not born. Gene therapy is among these methods. Yet it seems to have the advantage of neither ending, nor preventing from starting, certain possible lives. Rather it allows the continuation, with improvements, of a life already under way. But is this true? I consider what two influential identity theorists will have to say about this problem. A Kripkean account strongly suggests that therapy does not affect the identity of the person who will be born. But a Parfittian account, in contrast, appears to hold that insofar as psychology is affected, so too is identity. Of the two, I favour Parfit's account. Gene therapy, performed on a human embryo, can affect the identity of the person to be born. But then I go on to argue that the disagreement that is here resolved was never as profound as it might have appeared. Although there are scientific questions about the physical and psychological results of gene therapy, and although there are questions too about the links between different parts of our discourse, there is not, I claim, any deep issue about the nature, or the metaphysics, of identity.