The US government is being sued for compensation by hundreds of Guatemalan prisoners, psychiatric patients and orphans who were deliberately infected with syphilis (photo, from bbcimg.co.uk) or gonorrhoea in medical tests between 1946 and 1948.
Syphilis can cause blindness, insanity and even death.
They claim to have been infected without their consent in a programme to study penicillin.
Lawyers for the Guatemalans and their relatives filed a class action lawsuit.
Although last year the US apologised for the “reprehensible” experiments, lawyers said the Obama administration had not responded to a request for an out-of-court compensation settlement.
For decades the study carried out by US scientists was kept secret, until Prof Susan Reverby at Wellesley College in the US unearthed hidden records.
Last year she made them public.
She said that although the Guatemalan government of the day gave permission for the tests, the people infected were unaware they were being experimented on.
In the experiments, researchers bribed care workers to let them inject their charges and prisoners were encouraged to sleep with infected prostitutes.
When the evidence of the programme came to light, Alvaro Colom, the current Guatemalan president, said the tests were a “crime against humanity”.