More than 800 children in England – some as young as ten – are being given controversial drugs to help them change gender.

The NHS treatment, which halts the onset of adulthood, is aimed at young people who believe they are trapped in the wrong body.

Powerful monthly hormone injections stop the development of sex organs, breasts and body hair, making it easier for doctors to carry out sex-swap surgery later.

Until now it was thought that just a handful of children and teenagers were receiving the injections, known as ‘puberty-blockers’.

Pictured: Llyr Jones, from Aberystwyth, who said she would have killed herself without drugs

I had treatment last year – and it saved my life Pictured: Llyr Jones aged five. Llyr, who was born male, started living as a girl when she was 15 years old Teenager Llyr Jones has been taking puberty-blocking drugs for the past six months. The 17-year-old told how she was desperate to be prescribed the injections to end the agony she was going through as her body began to change into that of an adult man. Llyr, from Aberystwyth in Mid-Wales, said if the physical transformations that came with puberty had been allowed to continue, she would have been pushed to take her own life. ‘In all honesty, if I hadn’t been allowed to be on the blockers and start my transition, I’m sure I wouldn’t be here now,’ she said. ‘The worst thing was starting to grow body hair. It felt like something was happening that wasn’t me – I was so uncomfortable. ‘Some days were worse than others when I would catch a glimpse of my body in the mirror and I’d collapse on the bathroom floor for hours, frozen with distress.’ Llyr, who was born male, started living as a girl when she was 15 years old. Previously she had suppressed her desire to become female because of the bullying she endured for ‘being different’ in the small Welsh farming community she grew up in. ‘I didn’t want to give my bullies yet another reason to go after me,’ she said. Llyr finally found relief in January last year when she was sent to London’s Tavistock gender identity clinic, which has seen a dramatic increase in referrals – from 94 in 2009/10 to almost 2,000 last year. After being psychologically assessed and diagnosed with gender dysphoria, she was then sent in November for medical treatment at University College Hospital in London. There she underwent a series of health checks, including blood tests and bone scans, before doctors finally prescribed the puberty-blockers that Llyr now believes saved her life. ‘I thought thank God, because I knew they were stopping the puberty,’ she said. Since starting the blockers, Llyr said she has become more confident and at ease with her body. The next stage, she says, will be surgery, which can happen legally from the age of 18. She thinks the operations are unlikely before she is 19 because of the current waiting lists. Dressed fashionably in a colourful crop top and shiny black trousers, a carefree Llyr declared: ‘I’m just in such a great place now because I know after everything I’ve been through, I’m on the right track.’ Pictured left and right: Llyr Jones by the sea. The next stage, she says, will be surgery, which can happen legally from the age of 18 Advertisement

But The Mail on Sunday can reveal that more than 600 young people are undergoing treatment at the Gender Identity Development Service clinic at University College Hospital in London, and a further 200 at a clinic in Leeds. The MoS has been told that 230 of those 800 are under the age of 14.

The huge growth in the number of youngsters being prescribed the drugs came after the NHS scrapped the age limit in 2014, which was previously 16.

Now doctors can give the injections to children from the very early stages of puberty – meaning that in some cases, ten-year-olds are receiving them.

The MoS revelation comes a week after the Government announced plans to allow adults to legally change their sex without a medical diagnosis. In future, individuals who want to change gender are expected to simply make a statutory declaration that they intend to live in the sex they have transitioned to until death.

Last night Mary Douglas, a spokeswoman for Grassroots Conservatives campaign group, said: ‘Adolescence is the age when you’re in a turmoil because you’re trying to work out who you are and gender is a big part of that.

London’s University College Hospital, above, is treating more than 600 children with puberty-blocking drugs

‘So to introduce such powerful medication into that is unwise.

‘This drastic notion that we should change our gender should be a last resort. Caution needs to be the watchword for everyone engaged in this, including doctors.’

Stephanie Davies-Arai, of Transgender Trend, a parent group concerned about the rise of children identifying as the opposite sex, added: ‘These kids are not old enough to make life-changing decisions that will affect them for the rest of their lives. It’s unethical to pursue this line of treatment with children who cannot possibly understand what they’re doing.’

Professor Gary Butler, the lead clinician for the gender identity service in London and Leeds, revealed how many youngsters are now taking puberty-blockers. He defended the use of the drugs and said critics did not appreciate the distress puberty can cause transgender young people or how much ‘relief’ the blockers can give to these patients and their families.

Pictured: Prof Gary Butler, who defended the use of the drugs and said critics did not appreciate the distress puberty can cause transgender young people

However, other medical experts have questioned the safety of the treatment, warning that little is known about its long-term mental, psychological and physical effects.

Last month three top US doctors, Professors Paul Hruz, Paul McHugh and Lawrence Mayer, published a highly critical report on the use of puberty-blockers to treat gender dysphoria.

Writing in American academic journal The New Atlantis, they warned that the safety of this ‘experimental’ treatment was ‘unsupported by rigorous scientific evidence’.

They further argued that the use of such drugs may be driving children to ‘persist in identifying as transgender’. Research shows that the vast majority of under-16s who are troubled about their gender do not go on to take the drastic step of surgery. Meanwhile, the three professors point to another study from a Dutch clinic – where all the adolescents prescribed puberty blockers had gone ahead with gender-reassignment surgery – as evidence that the drugs can ‘solidify’ patients’ feelings they were born the wrong biological sex.

Pictured: How the Mail on Sunday has led the way in reporting this highly contentious issue

Pictured: How the Mail on Sunday has led the way in reporting this highly contentious issue

Concern has also been raised about the blockers’ long-term impact on bone health. But Prof Butler said the drugs have no ‘permanent effects’ on the reproductive system or the body as a whole.

‘When you stop the blocker, the puberty hormone process just starts up again within a couple of months. If you’ve gone through puberty already, you start where you left off,’ he said. ‘You don’t go back to the beginning again. If you haven’t gone through puberty, you would just complete the full puberty development process.

‘You would go through it at the same rate as you would if you hadn’t taken the blockers, but the timing will just have been delayed.’

He also insisted that the drugs were safe because they had already been used for decades to treat other conditions such as fertility problems in women and prostate cancer.

Addressing fears about the effects the drugs can have on bone development, Prof Butler said there was no need to ‘worry unduly’. ‘Our preliminary analysis suggests that the blocker just halts bone-calcium increases – it doesn’t weaken the bones directly,’ he added.

Prof Butler said his gender identity clinic now ‘routinely’ prescribes puberty-blockers to children diagnosed with ‘life-long’ gender dysphoria – the belief that a person is inhabiting the wrong sex.

‘When the team feels the young person is genuinely transgender they welcome [the use of] puberty-blocking drugs right from the early stages,’ he said.

His clinic has treated more than 600 under-18s with the blockers and Leeds Gender Identity Service has prescribed them to a further 200, he said. Of these, he said ‘about 230’ were 14 or under – with the youngest being ten. His disclosure comes three years after The Mail on Sunday revealed how NHS doctors were set to give the puberty blockers to nine-year-olds – causing outcry from critics who accused them of ‘playing God’ with children’s lives.

Explaining the process, Prof Butler said his patients were first ‘carefully’ psychologically assessed by experts at the NHS’s nearby Tavistock Clinic. ‘We then do medical assessments to see if the young person has started puberty and how far they are into puberty,’ Prof Butler said.

If suitable, both physically and psychologically, they then advise GPs to prescribe the blockers.

He added: ‘We’re lucky in the UK that people don’t miss out – they will get this treatment.’

Experimental treatment endangers children, writes professor of psychiatry Paul McHugh

Advocates of puberty-blockers argue that it represents a prudent and ‘fully reversible’ way to give young people with gender dysphoria and their families time to sort out the difficult issues surrounding gender identity.

Puberty-suppression as an intervention for gender dysphoria has been accepted so rapidly by much of the medical community, apparently without scientific scrutiny, that there is reason to be concerned about the welfare of children who are receiving it.

There remains little evidence that puberty-suppression is reversible, safe, or effective for treating gender dysphoria.

Psychologists do not understand what causes gender dysphoria in children and adolescents.

They also cannot distinguish reliably between children who will only temporarily express feelings of being the opposite sex from children whose gender dysphoria will be more persistent.

We frequently hear from neuroscientists that the adolescent brain is too immature to make reliably rational decisions.

But we are supposed to expect emotionally troubled adolescents to make decisions about their gender identities and about serious medical treatments at the age of 12 or younger.

For patients and doctors who are committed to the view that the young person’s gender dysphoria represents a persistent and real problem that can best be solved by transitioning the patient to living as the opposite sex, puberty-suppression can seem like a desirable approach.

But most children who identify as the opposite sex will eventually come to identify as their biological sex.

Until much more is known about gender dysphoria, and until controlled clinical trials of puberty-suppression are carried out, this intervention should be considered experimental.

Regardless of the good intentions of the physicians and parents, to expose young people to such treatments is to endanger them.