Adolf Hitler learned about eugenics from sterilisation clinics in America, according to a renowned academic.
Yale University historian Daniel Kevles, who has recently retired, made the astonishing claim in reference to a string of genetics laboratories which sprang up in America around the turn of the 20th century, according to the BBC.
Although Kevles believes Englishman Francis Galton, a cousin of Charles Darwin, was the founding father of eugenics in the mid-19th century, the idea was adopted in America as a solution to the social problems caused by mass immigration and urban overpopulation after the country's civil war.
The historian said that "because America seemed to find itself 'degenerating'" due to problems such as povery, alcoholism and prostitution, support for eugenics crystallised in a series of research centres, and the movement "went through the roof" after a landmark legal case in 1927 ruled that sterilisation was valid under the US constitution.
During the 1930s a wide range of perceived ailments and disabilities - blindness, epilepsy and mental illness among them - were treated with sterilisation, and some states continued the practice for years after the Nazis' crimes had emerged. In fact the state of Virginia continued to sterilise people until 1979.
In total it is estimated that up to 70,000 people were sterilised across the United States, in centres such as the Cold Spring Harbour laboratory, an hour away from New York, which is still active today and admits its role in propagating eugenics on its website.
"If you mention the word 'eugenics' many people associate it with the Nazis and the Holocaust," Kevles said. "But this is erroneous.
"In fact, Hitler learned from what the Americans had done."