In this article, I argue that lawmakers must abandon their previous reluctance to engage with questions of personal identity (PI). While frequently seen as an esoteric subject, of limited interest outside of academic philosophy departments, I attempt to show that, in fact, assumptions about PI—and its durability in the face of certain psychological or genetic changes—underpin many current legal rules. This is most perhaps obviously exemplified with regard to reproductive technologies. Yet the Parfitian challenge to identify a victim of ‘bad’ (...) reproductive choices has been largely overlooked in framing legislative responses to such technologies. Furthermore, I argue, it is not only with regard to emerging technologies that questionable assumptions about PI play a role; legal responses to questions about the attribution of criminal responsibility, and about the treatment of demented or brain-injured people, necessitate a frank engagement with such questions. It may be, however, that a multi-faceted approach to PI, which takes account of genetic, psychological and social factors—will prove a better fit for the myriad needs of the legal system than any sort of ‘unified theory of identity’. (shrink)