In 1946 orphans in Guatemala City, along with prisoners, military conscripts and prostitutes, had been selected for a medical experiment which would torment many, and remain secret, for more than six decades.
The US, worried about GIs returning home with sexual diseases, infected an estimated 1,500 Guatemalans with syphilis, gonorrhoea and cancroid to test an early antibiotic, penicillin.
The US government admitted to the experiment in October when the secretary of state, Hillary Clinton, and the health secretary, Kathleen Sebelius, issued a joint statement apologising for "such reprehensible research" under the guise of public health. Barack Obama phoned his Guatemalan counterpart, Alvaro Colom, to say sorry too.
Susan Reverby, a professor at Wellesley College in the US, uncovered the experiment while researching the Tuskegee syphilis study in which hundreds of African American men were left untreated for 40 years from the 1930s.
The Guatemalan study went further by deliberately infecting its subjects. Not only did it violate the Hippocratic oath to do no harm but it echoed Nazi crimes exposed around the same time at the Nuremberg trials.