In the mid-1990s, child mental health researchers at top New York institutions injected grade-school boys with fenfluramine, also known as the diet drug "fen-fen," a substance that was later banned by the Food and Drug Administration, due to its links to valvular heart disease and pulmonary hypertension. The boys were all Black or Hispanic by design: Eligible participants were required to be African American or Hispanic because they were deemed to be at higher risk for developing disruptive behaviors.