The Medicines and Healthcare products Regulatory Agency (MHRA) has introduced new minimum age requirements for participation in the heavily debated PATHWAYS Trial, a study investigating the effects of puberty blockers in young people experiencing gender incongruence.
Under the revised guidance, birth-registered female participants must be at least 11 years old to enrol, while birth-registered male participants must be aged 12 and above. These amendments follow the trial’s suspension in February 2026 over safety concerns for its prospective subjects, and form part of a wider set of regulatory safeguards introduced by the body.
What is the PATHWAYS Trial?
Led by King’s College London (KCL), the PATHWAYS Trial aims to address ongoing uncertainty surrounding the effects of puberty blockers in children and adolescents suffering from gender dysphoria.
The study employs a randomised controlled trial design, with participants assigned to one of two groups: the first beginning treatment immediately and the second after a 12-month delay. By comparing outcomes between them, researchers hope to determine whether earlier access to treatment leads to improved outcomes for young people and whether delaying treatment reduces the risk of adverse effects.
More broadly, the trial seeks to strengthen understanding of the long-term physical, psychological, and social impacts of puberty blockers. Its findings may help to address a number of unresolved questions underpinning both medical and political debates surrounding the treatment.
The 2024 Ban on Puberty Blockers
The importance of the PATHWAYS Trial is closely linked to changes in UK policy introduced in 2024.
That year, the UK Government prohibited the routine prescription and private supply of puberty blockers to under-18s who were not already receiving them for the treatment of gender dysphoria.
The restrictions followed the publication of Dr Hilary Cass OBE’s Independent Review of Gender Identity Services for Children and Young People, commissioned by NHS England and NHS Improvement.
The report examined the evidence supporting existing treatment pathways and concluded that the effects of gender-suppressing hormones had not yet been conclusively established. As a result, clinicians lack sufficient evidence to determine their impact on the physical, social, and emotional wellbeing of those receiving treatment.
The PATHWAYS Trial can therefore be understood as an attempt to address the evidential gaps identified by the Cass Review. By generating more robust data on the benefits and risks of treatment, researchers hope to provide a stronger foundation for future clinical decision-making.
Cass also highlighted the increasingly polarised nature of conservations surrounding gender-related healthcare. Reflecting on the controversy associated with different treatment pathways, she wrote: “Despite the best intentions of everyone with a stake in this complex issue, the toxicity of the debate is exceptional.”
She concluded that providing the best possible standard of care to young people requires moving beyond hostility and focusing on evidence-based discussion: “There are few other areas of healthcare where professionals are so afraid to openly discuss their views, where people are vilified on social media, and where name-calling echoes the worst bullying behaviour. This must stop.”
Future Policy Implications
Although the 2024 prohibition was introduced on an indefinite basis, it is scheduled for review in 2027. Should the PATHWAYS Trial generate robust evidence demonstrating the safety and clinical benefits of prescribing puberty blockers to under-18s, policymakers may choose to reconsider the current restrictions.
For now, this trial forms part of the NHS’s wider effort to improve understandings of the effects of gender-suppressing hormones. Its findings are likely to play an important role in shaping future policy and informing decisions on the care provided to Britain’s gender-dysphoric youth.
By restricting participation to older children, regulators have sought to mitigate the study’s risks, while allowing it to proceed, nonetheless. This decision aligns with Dr Hilary Cass’s assessment that “more children will be harmed if we don’t do the trial than if we do”.
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