Chen Ning Yang was born in China, the son of a mathematics professor. He adopted Franklin as his first name in 1945 after reading the autobiography of Benjamin Franklin. Eventually, Yang studied under Enrico Fermi at the University of Chicago, where he earned his Ph.D. (1948) and then went on to make significant contributions to the theory of weak interactions in the field of particle physics and statistical mechanics. Yang is most widely known, however, for his work with Tsung-Dao Lee, for which they shared a Nobel Prize in 1957. Yang and Lee made a fundamental theoretical breakthrough by demonstrating the nonconservation of parity. As a result of their research, all scientific theories based on parity had to be reexamined. In 1964 Yang became an American citizen and assured the public in his Nobel Prize acceptance speech that he would never leave the United States because of his devotion to science, which, he believes, is primarily of Western origin.