Preventive medicine seeks to identify and control risk factors for disease before they cause illness. Accomplishing this goal often means intervening in patient behavior or administering treatment before the onset of symptoms—a measure viewed by some as an intrusion into personal freedom. Some even claim that medicine has begun to treat “risk factors” themselves as “diseases,” so that no one is entirely healthy. Remarkably, then, what appears to be an entirely laudable objective—prevention of disease—is coming under professional and ethical scrutiny.