From the moment babies are born, their gender identity is no secret. They are either a boy or a girl. As they grow up, most naturally fit into their gender roles. Girls wear dresses and play with dolls. For boys, it's trousers and toy cars. But some children insist they were born into the wrong body. They are transgender children, diagnosed with gender identity disorder, or gender dismorphia, and their parents insist it is not a phase. Tonight's documentary Transgender Kids (at 9:30pm on TV One) follows the lives of transgender children and sees their parents face life-changing questions. Most transgender children still live in the shadows, hiding from a world that sees them as freaks of nature. Rejected by their families, many grow up hating their bodies, and fall victim to high rates of depression, drug abuse and even suicide. No one knows why children are transgender - there are only theories. Some scientists suggest that a hormone imbalance during this stage of development stamped the brains of transgender children with the wrong gender imprint. Today, hundreds of families with transgender children - who have found each other over the internet - are taking a dramatically different course. They're allowing their children to live in the gender they identify with, in order to save them from a future of heartache and pain. Understanding Josie At the age of just six, Josie's determination to be a girl was causing his behaviour to become erratic. "As soon as we'd even praise her using a male pronoun she would just lose it," says Josie's mother, Vanessa. "She would throw herself down, she would cry hysterically, I mean the biggest tantrum you could imagine. She ripped the paper off the walls of her bedroom. "I caught her in the bathroom, she was in there for ages so I went in to find out what she was doing and she was standing there with her nail clippers in one hand and her penis in the other and it was like she was just willing herself to do it. And it was just terrifying." Josie was taken to a doctor and diagnosed with Gender Dysphoria, a condition where adults or children feel they are trapped in the body of the wrong sex. Josie is one of the youngest to receive this diagnosis. His parents could see no alternative but to allow him to become a girl. "It was really like a mourning time for me because I like, lost my child, it was my son and there was a long time when I didn't know what to do," says Josie's father, Joseph. "I would go to work, I would carry on my business, but inside I was just devastated over the loss." Vanessa says "We forced her and made her fit into a role that isn't hers. I forced her to be a boy that she isn't." Transgender Kids plays at 9:30pm tonight (Wednesday 17 February) on TVOne. TVNZ - 17th February 2010