 Now, as Hilleman was conducting these tests on children who had been volunteered by their parents, he was actually also testing the Mumps vaccine on another group of children, children who were living in state homes and had intellectual disabilities. They were essentially volunteered by the state. So until the law changed in the early 70s, this is how a lot of drugs, and particularly vaccines, were tested. This is actually something that comes up in Offit's interviews with Hilleman. This is a big ethical issue.