James Dewey Watson is an American molecular biologist, geneticist, and zoologist. In 1953, he co-authored with Francis Crick the academic paper proposing the double helix structure of the DNA molecule. Watson, Crick and Maurice Wilkins were awarded the 1962 Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material".

Watson was born in Chicago on April 6, 1928, as the only son of Jean (née Mitchell) and James D. Watson, a businessman descended mostly from colonial English immigrants to America. His mother's father, Lauchlin Mitchell, a tailor, was from Glasgow, Scotland, and her mother, Lizzie Gleason, was the child of parents from County Tipperary, Ireland. Raised Catholic, he later described himself as "an escapee from the Catholic religion". Watson said, "The luckiest thing that ever happened to me was that my father didn't believe in God."

Watson is an atheist. In 2003, he was one of 22 Nobel Laureates who signed the Humanist Manifesto.

Watson married Elizabeth Lewis in 1968. They have two sons, Rufus Robert Watson (b. 1970) and Duncan James Watson (b. 1972). Watson sometimes talks about his son Rufus, who has schizophrenia, seeking to encourage progress in the understanding and treatment of mental illness by determining how genetics contributes to it.