In 1937, Puerto Rico made sterilization free and legal for women, passing a eugenicist law advocated by activists from the mainland as a corrective to poverty and overpopulation. Doctors coerced or tricked poor women into getting "la operación" (a hysterectomy) after their second child's birth. In 1976, according to what was then the U.S. Department of Health, Education, and Welfare, more than 37% of women of child-bearing age in Puerto Rico had been sterilized.
During these decades, Puerto Rican women were also subject to medical experimentation (without their informed consent) as test subjects for the birth-control pill.