Puberty blocker trial to recruit kids as young as 11 within days after High Court rejects bid to stop it

By SHAUN WOOLLER, EXECUTIVE HEALTH EDITOR Published: 15:33, 31 July 2026 | Updated: 15:36, 31 July 2026 A controversial puberty blocker trial is expected to start recruiting kids as young as 11 within days after the High Court today rejected a bid to stop it. Campaigners wanted a judge to halt the ‘deeply unethical and highly dangerous’ trial, arguing regulators had acted unlawfully in approving it. They said proper safeguards were not put in place and they are concerned about the long-term physical and mental side effects on the children involved. But Mr Justice Chamberlain declined to give permission for a judicial review, sparking fury from the claimants, who are now considering an appeal. Some 226 kids are due to be given drugs to stop their body’s natural development as part of a government-backed trial, commissioned by former health secretary Wes Streeting. He had indefinitely banned the drugs after the Commission on Human Medicines said they posed ‘an unacceptable safety risk’. But he backed the Pathways trial into their side-effects, as recommended by the Cass review into the treatment of children who think they are trans. Puberty blockers are hormone-suppressing drugs that pause the physical changes which mark a transition towards adulthood, such as facial hair and periods. Keira Bell, a claimant in the High Court case, began taking puberty blockers when she was 16 before later ‘detransitioning’ has spoken of the long-term effects such treatments had on her. The trial, which was due to start recruiting children from tomorrow, has faced criticism surrounding the ethics of giving children a drug that could cause irreversible harm, including to their brains and fertility. James Esses, a psychotherapist and one of the claimants, said: ‘I’m deeply disappointed that we’ve been denied the opportunity to take this case to a full hearing in our pursuit to halt the deeply unethical and highly dangerous puberty blockers trial. ‘This judgment does not negate the serious and avoidable harm that will be caused if this trial is allowed to proceed. ‘Vulnerable children should never be used as guinea pigs in medical experimentation that may lead them down a path towards irreversible physiological and emotional damage, including infertility. ‘This trial is the antithesis of child safeguarding and I will now be consulting with my lawyers regarding the possibility of an appeal.’ The Cass Review recommended the trial after concluding that the quality of research claiming to show the benefits of puberty blockers for youngsters with gender dysphoria was ‘poor’. Girls as young as 11 and boys as young as 12 will be able to join after regulators watered down their objections. The launch was dramatically halted in February when the Medicines and Healthcare products Regulatory Agency expressed safety concerns and indicated it wanted to restrict the trial to kids aged 14 and over. The trial, which was due to start recruiting children from tomorrow, has faced criticism surrounding the ethics of giving children a drug that could cause irreversible harm, including to their brains and fertility. But researchers revealed last month that they planned to resume recruitment after officials agreed to the lower age threshold. King’s College London, which is leading the proposed trial, opposed the legal action along with the Health Research Authority (HRA) and the Department of Health and Social Care. Mr Justice Chamberlain ruled that questions about the safety, ethics and scientific design of the Pathways trial are matters primarily for specialist regulators and that the court should be slow to interfere with their assessment. But the claimants argue they were more concerned about whether regulators could lawfully approve a trial when they accepted that the benefits of treatment for individual participants remained uncertain and there were serious known risks of harm. The campaigners bringing the court case are Bayswater Support Group, which is made up of parents and guardians of children and young adults who identify as trans or non-binary, as well as Mr Esses and Keira Bell, who began taking puberty blockers when she was 16 before later ‘detransitioning’ and who has spoken of the long-term effects such treatments had on her. Ms Bell said: ‘It is a tragedy that the court has refused permission for this challenge to proceed. ‘The medical profession and morality do not always walk hand-in-hand. If they did, this trial would be out of the question. Dr Hilary Cass, whose review recommended the trial after concluding that the quality of research claiming to show the benefits of puberty blockers for youngsters with gender dysphoria was ‘poor’. ‘The push for this trial represents one aspect of a profound descent into the desecration of our humanity. ‘The protection of children should be an inviolate principle, but this clinical trial tells a different story. I know first-hand how much this process breaks you.’ Angus McCullough KC, for the campaigners, said in written submissions to the court hearing that the trial would involve children under the age of 16-years-old, half of which would begin the treatment straight away while half would start it a year later. The barrister told the court: ‘However compelling the scientific need for a clinical trial may be, arising from that dearth of reliable evidence, that cannot displace the safeguards embedded in the regulations for the protection of child participants in a proposed clinical trial.’ Jenni Richards KC, for the HRA, said in written submissions that a suggestion that a research ethics committee did not consider the trial group to have any direct benefits from the study is ‘unarguable’. She said the eligibility criteria for participation in the trial require that the young person’s clinician believes the young person has a ‘reasonable prospect of benefiting’, if they were to try puberty suppressing hormones. Andrew Sharland KC, for King’s College London, added to the Government’s argument that the aim of the trial is to investigate the benefits and risks of taking the hormones. He said: ‘The claimants complain that it is not possible, before the trial begins, to identify which individual participants will benefit. 'That is not a flaw in the trial - it is the premise on which the trial is ethically and scientifically justified.’ Responding to the judgement, Helen Joyce, director of advocacy at sex-based rights charity Sex Matters, said: ‘The High Court’s decision to refuse a judicial review of the puberty blocker trial is both devastating and inexplicable. ‘These drugs have been blocked for use in gender treatment in both the NHS and private practice because of increasing evidence that they cause serious, permanent harm to vulnerable children. ‘And yet a trial so badly designed that it cannot possibly produce any useful scientific data has inexplicably been given the go-ahead. ‘Interrupting children’s development into healthy, fully functional adults is a human rights abuse. ‘Doing it with no more substantial goal than finding out whether it cheers them up briefly, as the planned trial does, is ethically monstrous. ‘The history of medicine is littered with tragic stories of researchers and doctors convinced by faulty theories doing terrible harm in the name of healthcare. ‘Years later, public inquiries declare that “lessons must be learned”, but that is little comfort to the people whose bodies have been irreversibly harmed.’ The research team welcomed the court’s decision and stressed the study has ‘strict eligibility requirements’ and all children joining must have received ‘significant psychological and social support’. They added: ’The safety and welfare of young people will remain our highest priority in carrying out this research. ‘Pathways Trial is a carefully designed study to give much needed evidence about the potential benefits and risks of puberty suppression to improve NHS care.’