In 1932, the U.S. Public Health Service recruited 623 African American men from Macon County, Alabama, for a study of “the effects of untreated syphilis in the Negro male.” For the next 40 years—even after the development of penicillin, the cure for syphilis—these men were denied medical care for this potentially fatal disease. The Tuskegee Syphilis Study was exposed in 1972, and in 1975 the government settled a lawsuit but stopped short of admitting wrongdoing. In 1997, President Bill Clinton...