Children under 15 with a gender identity problem should be treated with puberty-delaying drugs to allow them to choose whether to live as males or females in later life, say draft guidelines from the US Endocrine Society. The guidelines state: "We recommend that adolescents who fulfil eligibility and readiness criteria for gender reassignment initially undergo treatment to suppress pubertal development."

The recommendations are largely based on the experience of a Dutch clinic where doctors have prescribed puberty blockers to more than 70 children under-16s. The youngest they have treated is 11, although the majority are 12 or over.

"We don't have any patient who has regretted their decision on the treatment," says Henriette Delemarre-van de Waal of Leiden University Medical Centre who has helped treat them.

However, even New Scientist, which normally champions radical approaches to bioethical issues, questions this. “Some 80 per cent of boys who experience transsexual feelings no longer feel this way when they grow up. There is some evidence that those who persist after the first flush of puberty are less likely to change their minds, but this has been based on a handful of cases. So too has our understanding of the side effects of delaying puberty - or in the case of those who go through with gender reassignment, preventing natural puberty from occurring at all.

“The issue becomes thornier still when you consider that the age of puberty is falling. Does, say, a 9-year-old have the emotional maturity to make a decision of this magnitude? Unlikely.”

However, Dr Marvin Belzer of Children's Hospital in Los Angeles, who has treated several 12 and 13 year-olds with puberty blockers, suggests that the procedure is ethical as long as the children give informed consent. “While it's possible that a teenager might change his or her mind,” he told New Scientist, “the question is, can we go back and say, 'yes, but you and your family had informed consent, and we knew that that was one of the risks, but that risk was small'." ~ New Scientist, Dec 10