In a time when almost everyone shares almost everything, the question of boundaries between a doctor and patient is thornier than ever. Beyond the obvious no-go areas of sex and abuse, the relationship can be fraught. How do you reply to the chatty doctor who name-drops other patients—including your co-workers? Can you invite your dermatologist to dinner? Doctors are divided on how strict the boundaries should be. Some have firm rules against socializing with patients or revealing personal details about their own lives. Others say a closer relationship can build trust and make it more likely patients will follow medical advice. [Subscription Required]