Normal functioning and the treatment-enhancement distinction.

The treatment-enhancement distinction draws a line between services or interventions meant to prevent or cure (or otherwise ameliorate) conditions that we view as diseases or disabilities and interventions that improve a condition that we view as a normal function or feature of members of our species. The line drawn here is widely appealed to in medical practice and medical insurance contexts, as well as in our everyday thinking about the medical services we do and should assist people in obtaining. In this paper I shall consider various objections to the treatment-enhancement distinction: that it is difficult to draw, that it does not give us the boundary between what is obligatory and nonobligatory in medical interventions, and that it leaves us with hard cases that make the distinction seem arbitrary. My qualified and limited defense of the treatment-enhancement distinction in this paper means it cannot provide a clear guide to the moral boundaries between what is obligatory and nonobligatory or between what is permissible and impermissible, though it has a useful, if modest, bearing on each.