The Melbourne’s Royal Children’s Hospital has defended its gender clinic after months of silence when being questioned about safety and ethics.

An open letter from RCH chief executive John Stanway and chairman Rob Knowles said the clinic led by paediatrician Michelle Telfer was “one of the world’s best” and its 2018 treatment guidelines had been “peer- reviewed at the highest level”.

The letter said treatment of children and teens who identified as transgender was “based on the best available medical evidence” and given under “strict clinical governance standards”.

The clinic and Telfer had been widely criticised after it was revealed puberty blockers were being offered to children as young as 10 years old. It was claimed they were administered to stop the “growth of distressing sex characteristic such as breasts”. There is also a push for breast removal for under 17 year old’s.

Numbers at the clinic are sky rocketing, “with the clinic expecting to reach a record 300 this year, a potential increase of 1567 per cent since 2012, when Dr Telfer took charge.”

Constant criticism has been levelled at the clinic by practitioners such as Sydney psychologist Dianna Kenny and Western Sydney University’s professor of paediatrics John Whitehall. Both have warned about the lack of research and potential harm of such treatments. Along with 200 other doctors they have called for a Parliamentary Inquiry into these practices.

Kenny noted the letter of defence simply contained “a motherhood statement” with no specific details.

There has also been “international criticism for overplaying empirical evidence and lacking caution.”

American endocrinologist Michael Laidlaw, said “an experiment is already being conducted on children” and asked, “Why is there no comparison with psychotherapy, cognitive behavioural therapy, or watchful waiting?”

Binary spokeswoman, Kirralie Smith, said the clinic must be heavily scrutinised.

“We are talking about children. If there is any doubt or concern about transitioning why wouldn’t the clinic be encouraging strict and thorough investigations into all treatments and side effects? Why hide or deflect ? Medical practices should not be driven by an ideological agenda.”