I ONCE had the unenviable task of informing a 22-year-old Jamaican man that he was suffering from severe heart failure and would probably need a heart transplant. The man’s father warned me that his son would be devastated to hear the diagnosis. “It would mean a lot to me if you could go back in and tell him he’s going to be all right,” the father pleaded. “Please tell him that if he does the things you say, he’s going to be O.K.”

Though physicians are obligated to disclose all relevant medical information to their patients, it was obvious that this young man wasn’t prepared to hear the news I had to present. He was lying on his stomach, crying, refusing to turn around to talk to me. So I told him exactly what his father had requested. Then, over several days, I eased him into the knowledge of his true condition. Doctors sometimes have to know how to keep secrets.

The moral basis for withholding information from such a patient is clear: Above all, physicians must do no harm. The underlying philosophy is paternalism. Paternalism derives from the image of the paternal figure, the father, in a family. The father is motivated by an interest in his children’s welfare. He acts on their behalf, but not at their behest. The beneficiaries — his children — may even repudiate the actions taken on their behalf.

Such paternalism was once widely accepted in medicine. In the mid-19th century, the American Medical Association’s code of ethics stated that physicians had a “sacred duty” to “avoid all things which have a tendency to discourage the patient and depress his spirits.” But times have changed. The prevailing ethical mantra in medicine is patient autonomy. Today, patients own their health information. They have the right to direct their own care, and to do so they must be fully informed. As doctors, we no longer “care for” as much as “care with” our patients through their illnesses.