Paul Polani (1914Polani ( -2006 was one of the key figures internationally in the beginnings and development of medical genetics. Best remembered scientifically for his highly original work on the basis of human sex chromosome disorders, notably Turner syndrome, he pioneered the application of basic biological research to clinical genetic problems. The unit that he founded in 1960, at Guys Hospital, London, provided an unparalleled model for combined research and service in medical genetics across a wide range of laboratory areas and helped to establish medical genetics as a specific discipline.