Barrowman seeks to answer the question: why am I the way I am? In this one-hour special, Barrowman sets out to unearth what the latest scientific research can tell him about the origins of his homosexuality. His search for evidence takes him back to his roots to meet family and old friends. He also meets with psychologists and geneticists, compares his DNA to his heterosexual brother's, and conquers his claustrophobia to undergo a brain scan - all in the quest to find out how nature and nurture might have interacted to make him who he is. Barrowman tells the BBC: "My sexuality has never been deliberately hidden. I'm in a committed relationship with the love of my life, Scott Gill, and he is as much a part of the family as my sister's husband, Kevin, and my brother's wife, Dot. However, just because I'm comfortable with my sexuality doesn't mean that I'm not curious about it and that's one of the reasons I agreed to take this journey to discover the making of me."
When double world champion hurdler Colin Jackson was competing professionally, he refused to have a scientist or a psychologist come within a mile of him. He believed his talent was mainly something he was born with and he didn't want anyone meddling with it. Now that he's retired from sport he's agreed that scientists "can take me apart and really see what made me a champion". For this film he goes through extraordinary scientific hoops to find out whether he was born a natural athlete (he was walking by nine months, started running a few months later - and didn't stop running for the next 35 years!) or whether it was just hard work that turned him into a world champion. The tests throw up some interesting ideas: there's evidence that the month you are born can affect your chances of becoming a top athlete; and ethnicity may play a part, too. But it's the results of a muscle biopsy that really astound him.
Having first hit the international music scene aged 10, Vanessa-Mae's 8 million record sales have propelled her onto the Rich List and into celebrity status. But can science explain the secret of her success? Was she born a musical prodigy or did the powerful influence of her mother shape her musical talent? Determined to find some answers, Vanessa is tested by psychologists, confronted by a roomful of twins, and even put in the hot seat of a racing car to answer a question that affects us all. Nature or nurture - which makes us what we are?