Nobel Prize-winning scientist James Watson has been stripped of his honorary titles at the laboratory he once led after doubling down on racist comments.

Watson, who discovered DNA’s double helix structure alongside Francis Crick and Rosalind Franklin in the 1950s, said that genes cause a difference on IQ tests between blacks and whites, in a recent PBS documentary "American Masters: Decoding Watson."

The leaders of Cold Spring Harbor Laboratory on Long Island said in a statement his comments were “reprehensible, unsupported by science.”

This isn't Watson’s first controversial comment about race. He lost his position as chancellor at the lab in 2007 after he told the Sunday Times he was “inherently gloomy about the prospect of Africa" because "all our social policies are based on the fact that their intelligence is the same as ours, whereas all the testing says not really."

He added that although he wished everyone were equal, “people who have to deal with black employees find this not true.”

His comments in the documentary “effectively reverse the written apology and retraction Dr. Watson made in 2007,” the lab’s statement read. As a result, the lab stripped him of his titles of Chancellor Emeritus, Oliver R. Grace Professor Emeritus and Honorary Trustee.

Watson became the first person to sell his Nobel Prize in 2014 as part of an attempt to restore his reputation, the New York Times reported.

His son Rufus told the Associated Press that his 90-year-old father is recovering at home from a car crash in October and has “very minimal” awareness of his surroundings.

“My dad’s statements might make him out to be a bigot and discriminatory,” he said. "They just represent his rather narrow interpretation of genetic destiny.”

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