The first approach to defining the line between treatment and enhancement appeals to the health professions’ conventional vision of their proper domain. Accordingly, “treatments” are any interventions that the professional standards of care endorse, while “enhancements” are any interventions that the professions declare to be beyond their purview. Attempts by professional societies to police their own frontiers by discouraging particular practices as “enhancement” rather than “treatment” reflect this approach, as do appeals to “community standards” by health care payers seeking to distinguish “elective” from “medically necessary” interventions for payment.