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Puberty Blockers Clinical Trial
23 March 2026
Lead MP
Jamie Stone
Caithness, Sutherland and Easter Ross
Lib Dem
Responding Minister
Karin Smyth
Tags
NHS
Word Count: 11961
Other Contributors: 23
At a Glance
Jamie Stone raised concerns about puberty blockers clinical trial in Westminster Hall. A government minister responded.
Key Requests to Government:
The hon. Member asked that the Government ensure rigorous research to understand both the potential harms and benefits of puberty blockers for treating gender dysphoria, emphasizing the importance of high-quality data in making sound judgments about their use. Will the Department engage with advocacy groups like TransActual? Will it reinstate the trial while ensuring those not participating can still receive appropriate healthcare? Will it revise its policy to remove arbitrary age limits for hormone prescriptions? Will it reduce waiting lists which are currently over six years?
How the Debate Unfolded
MPs spoke in turn to share their views and ask questions. Here's what each person said:
Lead Contributor
The hon. Member Jamie Stone expressed concerns about the clinical trial for puberty blockers, citing possible long-term medical side effects such as reduced bone density and uncertain impact on brain development. He also questioned whether meaningful consent can be obtained from children or adolescents due to the complexity of fully grasping the long-term implications. My constituents are anxious about the pausing of the trial. Trans youth need access to gender-affirming care for their wellbeing, as per international best practice. The pause is causing anxiety among many individuals.
Carla Denyer
Green
Bristol Central
Ms Denyer expressed concern about the political nature of pausing the PATHWAYS trial and argued for research to be inclusive and centred on young people's needs. She supported puberty blockers as a safe and reversible treatment, recognising their value in reducing gender dysphoria.
Carla Lockhart
DUP
Upper Bann
Children deserve protection, not experimentation. In Upper Bann, over 1,300 people signed a petition against the clinical trial of puberty blockers. The speaker argued that animal testing has shown irreversible damage to brain development from puberty blockers and questioned why such hormones are being used in children if they are deemed unfit for animals.
Caroline Johnson
Con
Sleaford and North Hykeham
Ms Caroline Johnson, an NHS consultant paediatrician, expressed concerns about the puberty blockers trial for gender incongruence. She questioned the ethics of treating children with risky medication to provide cosmetic benefits to a smaller group of adults in adulthood. Johnson also pointed out potential long-term health risks such as fertility problems and bone demineralisation, highlighting issues with patient selection, trial design flaws, and lack of transparency from the MHRA.
David Smith
Lab
North Northumberland
Mr Smith urged the Government to cancel the PATHWAYS trial due to concerns over unreliable diagnosis and potential harm. He cited Dr Cass's review, which questioned the rationale for early puberty suppression, highlighting the need for a compassionate and holistic approach.
Emily Darlington
Lab
Milton Keynes Central
Asserts that not providing treatment like puberty blockers can harm young people, citing long wait times and scientific evidence. Criticizes the MHRA for changing its stance on the PATHWAYS trial due to political pressure rather than new research findings.
Graham Stringer
Lab
Blackley and Middleton South
The hon. Member is making great efforts to be balanced in his presentation, but I argue that we should not experiment on children, especially as double-blind experiments are impossible.
Gregory Stafford
Con
Farnham and Bordon
Stressed the need for caution in children's healthcare and criticised the lack of robust proof that puberty blockers deliver claimed benefits. Raised ethical concerns over administering drugs to young children with no reliable prediction methods, questioning the design of the trial and its approval process. Will the Minister give way?
Helen Morgan
Lib Dem
North Shropshire
Liberal Democrats have been arguing for improved access to specialist healthcare services for young people struggling with their gender identity, welcoming the call in the Cass review for a clinical trial. The speaker highlighted the need for new regional centres and criticised long waiting lists of over 5,000 young people with an average wait time of three years for first appointments. She urged the Government to show true urgency in opening these services and called on the NHS to build up evidence effectively and safely.
Iqbal Mohamed
Ind
Dewsbury and Batley
The trial prioritises the interests of a small number of children at the expense of those who may outgrow gender dysphoria. There is evidence that over 95% of children starting puberty blockers continue to cross-sex hormones, while up to 60-98% naturally overcome their dysphoria. Asked if he could give way, but no further content provided. Will the Minister give way?
Jim Allister
TUV
North Antrim
Adolescents are among the most vulnerable in society. Gender dysphoria often resolves naturally during puberty, yet there was no restraint on puberty blockers before 2024. The trial lacks a due process of consent and may have medical consequences for children's bone density and brain development.
Jonathan Hinder
Lab
Pendle and Clitheroe
Mr Hinder criticised the ethical implications of the puberty blockers trial, arguing that it risks permanent physical damage and infertility in healthy children. He emphasised the need for compassion and support rather than medical intervention, asserting that puberty is a natural part of development.
Josh Newbury
Lab
Cannock Chase
Mr Newbury acknowledged the strength of feeling on both sides and emphasised the importance of evidence-based decision-making. He stated that cancelling the trial would deny trans young people a necessary evidence base for safe treatment, urging colleagues to reflect on the consequences.
Joy Morrissey
Con
Beaconsfield
The clinical trial is flawed and exposes children to potential harm without a sound basis. The ICD-11 diagnosis required for participation is subjective, making the long-term risk of medical intervention unjustifiable.
Julian Lewis
Con
New Forest East
Many children were treated with puberty blockers before the Gender Identity Development Service programme was closed down, and I question what has happened to all the data from those previously treated children.
Rachel Taylor
Lab
North Warwickshire and Bedworth
The need to build an evidence base through clinical trials is crucial, but there are concerns that the Medical and Healthcare Products Regulatory Agency (MHRA) has reversed its initial approval due to pressure from lobbying groups. This shift raises questions about the independence of regulatory decisions. Will the Minister give way?
Rebecca Paul
Con
Reigate
Ms Paul argued that using puberty blockers on healthy children is deeply wrong, citing potential long-term health impacts such as infertility, bone density loss, and psychological harm. She raised concerns about the rigorousness of the approval process for the trial.
Rebecca Smith
Con
South West Devon
Expressed concerns about the medicalisation bias in NHS trials and highlighted that looked-after children were over-represented, with referrals making up 5.9% despite being only 0.6% of the general population. Also raised issues regarding the treatment of young lesbians as if they were born in the wrong body, citing a significant percentage identifying as lesbian or bisexual.
Rosie Duffield
Ind
Canterbury
Ms Duffield highlighted the vulnerability of autistic children in the puberty blockers trial, noting that many rely on rigid stereotypes and seek affirmation from others. She acknowledged the work of medical professionals and journalists who have campaigned against the notion of being born in the wrong body and urged to stop the trial due to its impact on young, vulnerable individuals.
Sarah Pochin
Reform
Runcorn and Helsby
The motivation behind clinical trials is questionable, with concerns raised about the inclusion of vulnerable children, such as those in care or on drugs for anxiety or ADHD. There are also worries about parental consent requirements.
Scott Arthur
Lab
Edinburgh South West
Believes a trial for puberty blockers is necessary to understand their short and long-term impacts. Cites the case of a trans woman in his constituency who struggled with her mental health due to her gender identity, suggesting that puberty blockers could have alleviated some of her anguish.
Stuart Anderson
Con
South Shropshire
Ethically, there is no justification for allowing children to be experimented on with puberty blockers. What might be a short-term solution could become permanent and regrettable.
Thomas Tugendhat
Con
Tonbridge
Argues against experimenting on children with puberty blockers, emphasizing the need for caution and respect for children's vulnerability. Questions the government about legal costs related to potential detransitioning cases involving minors.
Tonia Antoniazzi
Lab
Gower
The hon. Gentleman is making a very good start to his speech, and I am concerned about the manner in which young people—children—are asked questions such as 'Have your parent(s) treated you fairly?' on the KIDSCREEN-10 index. Ms Antoniazzi briefly intervened to ask a question but her exact contribution was not detailed in the transcript.
Government Response
Karin Smyth
Government Response
It is a pleasure to serve under the chairmanship of David Mundell. The minister acknowledged the strength of feeling on the issue from thousands of petition signatures and assured that the government will always be led by science and put vulnerable children's health first. She highlighted Dr Hilary Cass's review which recommended better data and evidence for gender services, with a new model of care based on holistic assessment and psychosocial support. The PATHWAYS clinical trial was described as going through thorough scientific, ethical, regulatory safeguards and is paused until issues are resolved by the MHRA. The minister stated that safety is the driving consideration in every decision regarding this trial. She also mentioned the data linkage study for adults who were referred to the Tavistock clinic before its decommissioning. NHS England has prevented routine use of puberty-suppressing hormones and issued guidance against supporting prescribing agreements with unregulated providers due to serious safety risks. Three new services have opened in different regions since April 2024, and a fourth service is becoming operational at Cambridge University hospitals NHS foundation trust. These operate under a fundamentally different clinical model from the Tavistock clinic offering comprehensive support from multidisciplinary teams. The minister urged all hon. Members to continue engaging with evidence that best supports young people.
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About Westminster Hall Debates
Westminster Hall debates are a chance for MPs to raise important issues affecting their constituents and get a response from a government minister. Unlike Prime Minister's Questions, these debates are more in-depth and collaborative. The MP who secured the debate speaks first, other MPs can contribute, and a minister responds with the government's position.