By Nell Boyce ONE of the most repugnant episodes in the history of medical research is the Tuskegee Syphilis Study. From 1932 to 1972, American researchers followed 400 poor African Americans with syphilis to see how their disease progressed. Even after penicillin became available in the 1950s, the researchers withheld the cure, so that medical science could benefit from observing how syphilis would progress untreated. Such a horrible injustice could never happen today. Or could it?