High Court rules puberty blocker trial can begin

A controversial trial of puberty blockers for children aged 11 and 12 can now start after an attempt to stop it was thrown out by the High Court.

The puberty blocker trial would allow girls aged 11-years-old and boys aged 12 with gender dysphoria to take the medication. Puberty blockers halt the normal changes of puberty, such as facial hair and periods. The judge ruled that the decision to approve the trial was “quintessentially a question of judgment” for the health authorities. The trial will now start, with up to 226 children expected to enrol.

Puberty blockers were stopped on the NHS in 2024 shortly before Baroness Cass’ independent review into child gender services. That review found that there was “remarkably weak” evidence for the use of puberty blockers, and that gender services for children in the UK has been operating on “shaky foundations”.

Cass’ review recommended a trial for puberty blocker medication, and this was initially set up by King’s College London. However the trial was paused earlier this year after concerns from the Medicines and Healthcare products Regulatory Agency (MHRA) about “potentially significant” biological harm from the drugs. The MHRA suggested introducing a minimum age of 14 for the medication. Revised protocols then allowed the trial to continue for children aged 11 and 12.

Campaigners from the Bayswater Support Group, which represents parents of gender-questioning children, Keira Bell, who took puberty blockers before ‘detransitioning’, and James Esses, a psychotherapist, tried to block the trial at the High Court. They argued that MHRA and the Health Research Authority acted unlawfully by approving the study without considering the long-term effects on children’s bone development, fertility, brain development and psychological wellbeing, and that there were flaws in the study’s design.

James Esses said: “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.” A spokesman for Bayswater Support Group said: “We brought this challenge because we believe the decision to authorise a clinical trial of puberty blockers in children failed to meet the protective requirements that exist specifically for research involving minors. We remain of the view that the … trial does not meet the legal and ethical thresholds required for research on children.”