Using the latest DNA technology, scientists are identifying the genes which help to determine the kind of people we are. In an exclusive interview, Nobel Prize winner Dr James Watson , who helped to discover the structure of DNA, warns their work may harm our lives as well as improve them. Steve Bradshaw analyses the genetic revolution with scientists, Baroness Warnock, and some of the people whose lives have already been profoundly affected by choices that may later confront us all.