Parfitian Priority, Gene Therapy, and Disability

Gene therapies for severe genetic disease are often highly expensive. In deciding whether or when to provide them, one ethical consideration is the benefit of treatment relative to cost. Another and separate consideration is concern for medical need and the desire to benefit those who are worse off. The latter is a prioritarian concern. But how should we apply prioritarianism to decisions about gene therapy, particularly since such treatments might affect which individuals come into existence? That question is the main aim of this paper. I focus on a particular version of prioritarianism articulated and defended by Derek Parfit. My primary aim is to explore how, if we were to adopt such an account, we should interpret and practically apply this in medical ethics. In doing so, I assess how it fits with other elements of Parfit's philosophy. I defend a new "time-relative" version of priority.