UK Launches Controversial Puberty Blocker Trial Following National Ban
核心洞察
King's College London researchers will conduct a randomized controlled trial involving 226 children under 16 to assess the safety and efficacy of puberty-blocking drugs for gender incongruence (搜索).
The Pathways trial follows a UK-wide ban on puberty blockers (搜索) after the Cass Review found insufficient evidence of safety and clinical effectiveness for under-18s.
Critics question the trial's ethics and design, citing concerns about informed consent and the exclusion of children with unstable mental health or those already self-medicating with hormones.
Researchers from King's College London have announced details of a controversial clinical trial to evaluate puberty-blocking drugs in children with gender incongruence (搜索), marking the first such study since the UK banned these medications for gender treatment in 2024.
The Pathways trial will involve up to 226 children under 16 years old who are experiencing gender incongruence (搜索), following the government's indefinite ban on puberty blockers (搜索) after the Cass Review raised serious concerns about the lack of clinical evidence supporting their safety and effectiveness.
Trial Design and Methodology
The randomized controlled trial will divide participants into two groups: half will receive puberty-suppressing hormones (搜索) immediately, while the other half will wait 12 months before starting treatment. Children will be matched as closely as possible based on sex, pubertal stage, and neurodevelopmental conditions.
Prof Emily Simonoff, the study leader and professor of child and adolescent psychiatry at King's College London, explained that young people and their parents attending gender services "tell us that they don't know what to do - they look at the information that's out there and they don't know what's best for them."
The trial will examine multiple outcomes over two years, including quality of life, mental health, body satisfaction, cognitive function, brain development, and bone mineral density. This represents the first study to investigate the impact of puberty blockers (搜索) on brain development.
Strict Eligibility Criteria
Participants must meet several stringent requirements, including a formal diagnosis of gender incongruence (搜索), completion of comprehensive psychosocial interventions, and demonstration of sufficient understanding to provide informed consent. Children with unstable mental or physical health, those unable to consent, or those who have already taken puberty blockers (搜索) or cross-sex hormones (搜索) will be excluded.
However, data from Great Ormond Street Hospital (搜索) reveals that close to one in eight young people accessing NHS gender services have disclosed self-medicating with irreversible hormones, automatically excluding them from the trial. Hospital officials acknowledge this "may not be a true reflection" as some patients may not have disclosed such information.
Scientific and Ethical Concerns
The trial has generated significant controversy, with some clinicians and campaigners questioning its ethical foundation. Keira Bell, who previously challenged the Tavistock gender clinic in court, has threatened judicial review proceedings, calling it "disgusting" that children are being given drugs that have been banned as "unsafe."
Dr Hilary Cass, who led the review that resulted in the ban, expressed support for the trial, stating: "My review uncovered a very weak evidence base for benefits from the use of puberty blockers (搜索) for children and young people with gender dysphoria (搜索). In fact, some children had more negative than positive effects."
One researcher involved in early trial planning, who is no longer part of the team, described the meetings as "unlike any other clinical trial I've encountered," noting they "could easily list all the potential harms to monitor and how to test for them, but we didn't have a clear rationale for giving the drug in the first place."
Previous Research Limitations
The trial follows a previous study conducted by the now-closed Gender Identity Development Service (Gids) and University College London Hospitals (搜索), which showed no clinical benefit in 44 children. That study found "no changes in psychological function, quality of life or degree of gender dysphoria (搜索)," with later analysis revealing that approximately one-third of children saw their mental health deteriorate significantly.
Despite these findings, NHS England (搜索) allowed routine referrals for puberty blockers (搜索) in 2014, with an estimated 2,000 children under 16 receiving the treatment before Gids closed in 2024.
Measurement Challenges
The trial's primary outcome measure is health-related quality of life using the Kidscreen-10 questionnaire, which asks children ten questions about their previous week. However, concerns have been raised about relying primarily on subjective measures for assessing serious medical interventions.
Additional questionnaires will assess sexual attraction, body image, and suicidal ideation, with some parents describing certain measures as problematic. The Body Image Scale asks children to assess their satisfaction with more than 30 body parts, while the Utrecht Gender Dysphoria (搜索) Scale includes the statement: "It would be better not to live, than to live as my assigned sex."
Long-term Follow-up Questions
While the trial will intensively study children for two years, with annual monitoring for up to five and a half years while funding is available, questions remain about long-term outcomes. The Cass Review emphasized that "bone density is compromised during puberty suppression" and noted uncertainty about whether "there is full bone health recovery in adulthood."
A planned data linkage study to follow up on approximately 9,000 children previously seen at Gids has been blocked by NHS adult gender services, despite being described by Cass as "a unique opportunity to provide further evidence."
Future Implications
Children completing the two-year trial period will undergo clinical review to determine next steps. Those wishing to continue puberty blockers (搜索) may do so with approval from both their clinician and a National Multidisciplinary Team, with annual reviews required.
The youngest participants may be just 10 or 11 years old, potentially facing five to six years of suppressed development before becoming eligible for cross-sex hormones (搜索) at age 16. The trial team did not respond to questions about concerns regarding such prolonged developmental suppression.
Health Secretary Wes Streeting has acknowledged parliamentary concerns about the trial while emphasizing that it will have "ethics and safety at its heart." The study is expected to begin in January 2025, with first results anticipated in approximately four years, though long-term safety data may take decades to establish.