Name at birth: Alan Mathison Turing
Alan Turing was the mathematician who in 1937 suggested a theoretical machine, since called a Turing Machine, that became the basis of modern computing. During World War II, Turing led the team that succeeded in breaking German high-level secret codes, using the first practical programmed computer, called Colossus. In 1950 he suggested what has become known as "the Turing test," which is still the criterion for recognizing intelligence in a machine. (To describe the test simply: can a human, in a blind conversation, tell the difference between a human and a computer posing as a human?) Alan Turing was a homosexual, which was a crime in England at the time, and in 1952 he was tried and convicted. Given a choice between prison and estrogen treatments, he chose the treatments. In 1954 he died of cyanide poisoning, an apparent suicide.
Alan Turing was also an accomplished competitive runner… Google honored Alan Turning with a Google Doodle on its front page on June 23, 2012 — the centennial of his birth.