Dr Hilary Cass, author of the landmark review into gender identity services for children and young people, has asserted that a new trial examining puberty blockers is vital to reduce potential harm to gender-questioning children. Speaking to the BBC, Dr Cass expressed her strong conviction that "more children will be harmed if we don't do the trial than if we do." This comes after the government implemented a UK-wide, indefinite ban in 2024 on the prescription of these drugs by both the NHS and privately for under-18s seeking gender care.
Dr Cass believes that some of the risks associated with puberty blockers have been exaggerated, stressing that there is a genuine lack of understanding about their potential harms. She described the upcoming trial as "essential" to answer the fundamental question of whether these drugs are truly helpful. Participants will undergo close monitoring across physical, social, and emotional aspects of their wellbeing, with checks on critical areas such as bone density, brain function, and fertility. Dr Cass highlighted a concern that without a regulated trial, young people may resort to "unregulated and dangerous routes" to access such treatments, citing instances of 11-year-olds presenting in clinics already on irreversible testosterone.
The trial, initially announced in November but paused in February due to age limit discussions, is now set to begin recruiting children in August, pending ongoing legal challenges. King's College London (KCL) researchers have agreed on participation ages of 11 for those registered female at birth and 12 for those registered male at birth. Health Secretary James Murray confirmed in Parliament that future decisions on this matter would be based on clinical evidence, stating he had received "most robust assurances about the safeguards which are in place to protect young people involved in this trial from receiving harm."
However, the trial faces opposition from campaigners, including the Bayswater Support Group, who argue it is unethical and that children cannot give adequately informed consent for participation, especially given potential impacts on future fertility. A spokesperson for the group stated that the trial risks causing irreversible harm and will not definitively resolve "outstanding questions about puberty blockers." Conversely, Chay Brown, Healthcare Director of trans campaign group TransActual, views the trial as the only legal avenue for young people to access puberty blockers, advocating for the ban to be reversed and for comprehensive care for all trans individuals.
Dr Cass maintains that this complex issue requires resolution through clinical opinion and scientific evidence, emphasising that young people and their families have been underserved by NHS services for too long. The Conservative party has also indicated its intention to force a vote in the House of Commons, allowing politicians to weigh in on the matter.