E3MBP5 NHS logo on outside wall UK. Image shot 2014. Exact date unknown. Credit: Alamy
AN NHS trial of puberty-blocking drugs for children who think they are transgender can go ahead and sign up patients as young as 11.
Campaigners branded the experiment a “monstrosity” as it was approved by the medical regulator for a second time.
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The Pathways study was halted in February, before it had started, due to concerns about the lack of a lower age limit or fail-safe to remove participants with severe side effects.
On Friday the Medicines and Healthcare products Regulatory Agency said the trial can go ahead with minimum age limits of 11 for girls and 12 for boys.
It is a compromise from a suggested age limit of 14 in the MHRA’s concerns in February.
The new plans will also continue to study the participants for longer, and added more detail to warnings about possible side effects and fertility counselling.
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Doctors led by King’s College London will study the effects of puberty-blocking hormone drugs on around 200 teenagers prescribed them through NHS gender clinics.
The powerful medicines are so poorly understood that the Government has banned new prescriptions to under-18s except via this trial.
They block sex hormones including testosterone and oestrogen to prevent the development of breasts, genitals and body hair, giving patients the option to transition from one gender to the other.
Opponents argue it is unethical to experiment on vulnerable teens and that most would be fine with specialist mental health treatment for identity issues.
They say the drugs might cause long-term damage to fertility and brain and bone development.
They are trying to stop the trial through the courts, meaning it will remain on hold until at least August.
James Esses, a psychologist and campaigner behind the legal challenge, appealed to Health Secretary James Murray to “pull the plug on this monstrosity”.
He said: “We have no choice but to seek an emergency injunction to block a single child being recruited and given this poison.”
Helen Joyce, of the charity Sex Matters, said: “It appears that gender ideology has broken yet another institution.
“The MHRA’s mission is supposedly to ‘put patients first’ in everything it does, and yet it is signing off on a trial that does the opposite.
“It is already clear that puberty blockers are no solution to childhood gender distress, and that they cause unacceptable harm.”
Dr Louise Irvine, a GP and co-chair of the Clinical Advisory Network on Sex and Gender, added: “I am surprised and disappointed that the regulators have once again approved this trial.
“It will put children at risk of harm for no clear benefit – it is risky, badly designed, unethical and unnecessary.”
The research team said there have been “no major changes to the study design”, with it set to be the most detailed of its kind ever conducted.
It added the age limits because it was “highly unlikely” that anyone younger would have been accepted into the trial.
And the experts said the vast majority of children being treated for gender issues will still not receive the drugs.
The team said: “Our priority remains to safely and robustly investigate the benefits and risks of puberty suppression for young people with gender incongruence to improve the evidence base and inform NHS healthcare.
“We have worked extensively and openly with the MHRA to understand and resolve the questions they raised, which were not based on any new scientific evidence.”
The MHRA said: “The MHRA’s top priority is the safety and wellbeing of the trial participants.”
WHAT IS THE PUBERTY BLOCKER TRIAL?
NHS clinics treating children and teenagers who think they want to swap gender will give some of them hormone medication to halt puberty.
The super-strong drugs were prescribed unsupervised for years but this was banned in 2024 due to safety concerns.
In patients who think they are transgender they are used to control levels of the sex hormones testosterone and oestrogen to slow down puberty and prevent sexual development.
For example, this would stop girls’ breasts growing if they want to become boys, or prevent a boy’s genitals from growing or their voice from dropping if they want to become a girl.
Doctors say this buys patients time to have therapy and decide whether they want to fully ‘transition’ from one gender to the other.
It may also reduce distress caused by developing an adult body of a gender they do not feel comfortable with.
Scientific evidence of the treatment’s risks and benefits is extremely weak.
Medics running the new NHS trial say it will produce some of the best evidence to date on the safety and effectiveness of puberty blocking treatment, and inform how to treat trans young people in future.
But critics say it is unethical to experiment on mentally vulnerable but physically healthy children, and more research is needed first in laboratories and on animals.
The trial, known as PATHWAYS, is expected to begin in January and recruit around 200 under-18s to be treated and tracked as they grow up.
