AN INCREASING number of Australian children are receiving treatment at a special clinic for gender identity disorder, including hormone treatments to make them feel more like the opposite sex.

Since 2003, a publicly funded clinic at Melbourne's Royal Children's Hospital has treated 39 children and adolescents for gender identity disorder - a condition where a person feels trapped within a body of the opposite sex.

Seven of these children successfully applied to the Family Court to suppress puberty so they had more time to consider sex-change treatments in late adolescence or adulthood. Others have court applications pending, while some could not afford the legal costs or wanted to continue counselling.

All seven adolescents who had puberty suppressed went on to receive cross-sex hormone treatments at age 15 or 16 so they felt more like the sex they identified with. Surgery is only available to people over 18.

For biological males, oestrogen treatment encourages breasts and other female characteristics while softening testicles and making them smaller. For females, testosterone suppresses menstruation and encourages hair growth, muscle bulk and voice deepening, with the latter being irreversible. It also increases the size of the clitoris and increases erections.