Can training children in sports from an early age produce super-athletes? A Californian coach, Marv Marinovich, believes it does. He has developed a highly successful training technique which he perfected by using his own children as guinea pigs. It has turned his 21-year-old son Todd into one of the hottest properties in American football with a career that could make him a millionaire. Although his eldest daughter dropped out of the intensive training regime when she was 14, Marv has started again on his younger son, [text removed], aged 3. A former professional footballer, Marv says: "As far as I am concerned, performance is not about winning or losing but about the quality of the outcome." Producer Christopher Tau, himself the father of a young family, commends the loving and caring relationship Marv has with his children but says, "I am an athlete too, but I would never do that to my child." A British study of 450 young athletes looked at the physical and mental stress produced by intensive sports training in childhood and found that young bodies, not yet fully formed, are susceptible to serious, permanent injury. So are ambitious parents like Marv Marinovich putting their own children at risk?