"What I may see or hear in the course of the treatment or even outside of the treatment in regard to the life of men, which on no account one must spread abroad, I will keep to myself, holding such things shameful to be spoken about."

This quote from the Hippocratic Oath, which is traced back to ancient Greek medicine, shows that medical privacy is not a new idea. Physicians were expected to keep secrets, but there was little public concern because, as discussed earlier, medical care was much simpler so there was less information to worry about and few people handling it so there was little chance of the patient's privacy being breached. As discussed above, after World War II, medical care changed from simple care given by physicians to hospital-based team care. This change made medical care less personal and much more threatening. At the same time, the civil rights movement caught up to medicine.

In the 1960s and 1970s, patients started demanding a say in their medical care. Physicians were pressured to end the practice of hiding cancer and other fatal illnesses for patients. While this was a common practice, there was overwhelming evidence that patients wanted to be told about their illnesses and did better when they were told. Lying to patients about their condition also meant telling family members and sometimes others about the patient's medical condition, while withholding this information from the patient. This created tension between family members and the patient because the family members believed that had to follow the physician's advice and lie to the patient. Patients started demanding access to their medical records so they would know what was being done to them and why. The main concern was controlling care. Access to information and its control were important as they related to the care.

While there were many factors that lead to today's concerns with medical privacy, the single most important factors was acquired immunosuppression syndrome (AIDS) and its, cause human immunodeficiency virus (HIV) infection. In 1981, the first cases of AIDS were identified. It was suspected to be an infectious disease before its method of transmission was worked out. This lead to public fear of being in contact with persons with AIDS, a fear that was mixed with discrimination because AIDS started as a disease of gay men and drug addicts. There were many anecdotes about gay men being fired from their jobs or losing their apartments because they had AIDS or were feared to have AIDS. AIDS support organizations and civil liberties groups such as the ACLU starting looking harder at medical privacy and publicizing the potential consequences of having employers, landlords, and others learn about frightening medical conditions such as AIDS and cancer. It was also not unusual for persons with other serious or disabling illnesses to lose their jobs because their employers were afraid of increased health insurance costs and lower productivity.

AIDS advocacy groups pushed the issue of medical privacy beyond concerns with the unauthorized release of private medical information. The issue because preventing the discovery of a patient's HIV status, and, if the patient knew he was HIV positive, keeping the information out the patient's medical records and even keeping the information from the patient's physician. As discussed in the section on Public Health, this had a profound effect on public health practice and research. Medical privacy soon became a general patient's rights issue and not just a concern for persons with AIDS. The fear was discrimination in the workplace and the loss of health insurance. Workplace discrimination was a real problem related to medical privacy and lead to the passage of the Americans with Disabilities Act, which is discussed later in this section. Although fears about having losing one's medical insurance were used to drive medical privacy laws, insurability is not really a privacy issue.

People with individual, as opposed to group, medical insurance policies often lose their insurance if they develop a chronic disease. People with chronic diseases who are uninsured, or whose employers quit offering group medical insurance, have a lot of trouble finding coverage, and when they do it is very expensive. Until fairly recently, persons with chronic illness who were covered by group insurance could have coverage for their illness excluded from coverage if they changed employers. Many people saw this as a privacy problem that could be solved if they just had stronger privacy laws to protect medical information.