Despite the intensely personal moments that happen in hospitals, patient privacy can be elusive. Hospitals are multimillion-dollar corporations that look like shopping malls and function like factories. Doctors knock on exam room doors to signal they are about to enter — not to ask permission. The curtain that encircles the hospital bed always lets in a crack of light. Yet we do expect some degree of privacy in hospitals. We trust doctors with our secrets in part because they take a 2,000-year-old Hippocratic oath to respect our privacy, an oath enforced by laws like the Health Insurance Portability and Accountability Act.