The Willowbrook State School Experiments
During the 1960s, it was common to give doctors and scientists free reign over marginalized groups. Doctors who were studying Hepatitis B took advantage of this, and used a school for the developmentally delayed as their own personal petri dish.
The New York state school started to experience Hepatitis outbreaks, and doctors were sent out to study them. To ensure that they got good data, they deliberately infected kids with the disease. Most horrifyingly, though, was the fact that they had their parents’ permission to do so.