Just when you think you've uncovered all the possible types of unethical human experimentation ever done, history throws a new wrinkle at you. In the early 1970s, a birth control clinic in San Antonio gave indigent women fake birth control as part of a medical study.
There are probably about ten people walking around today solely because of a grossly unethical experiment. If you're wondering whether you're one of them, ask yourself if you were born in San Antonio in late 1971 or early 1972. During 1971, a San Antonio birth control clinic engaged in an experiment designed to study the side effects of an oral contraceptive. The clinic did this by doing a double-blind trial, during which they gave half of a group of female patients real contraceptives, and half of them placebos. Half way through the study, they switched groups. They then monitored the women's symptoms - other than sudden, unexplained pregnancy.
Few women are willing to take a gamble on whether or not their birth control is going to be placebo, and even fewer women were willing to do that before Roe v Wade. The clinic got "volunteers" because no one informed the women that they'd be getting a placebo. The women were told that they needed to use vaginal cream for birth control, but as many of the them were indigent, and all of them were under the impression that they would already be on birth control, there's no way to know how many were compliant. Of 76 subjects, ten became pregnant while on the placebo, and one got pregnant while on the actual birth control.