Clinicians gave their reasons for signing the open letter to Wes Streeting, Secretary of State for Health, and to the PATHWAYS trial regulators (HRA and MHRA) in December 2025.
The signatories and comments were updated in a follow up email to Wes Streeting on 13 January 2026.
Harm/Risk
I agree with the reasoning in the letter. Evidence shows that puberty blockers almost always lead to continuation to cross sex hormones and often then to surgery. Irreversible changes thus occur to children and adolescents who may later come to regret the decision. While genuine rare transgender cases have a long history, the statistics of the past two decades of transgender rates in the paediatric age group indicate an overdiagnosis epidemic. Please see the website http://www.detrans.ai that indicates the growing regret and detransition rates and grief over irreversible changes made before the capacity for experience and adult formal operations reasoning.
I am deeply concerned that this trial, by its very design, will not yield results that carry the quality of evidence required to for decision-making, and on the contrary has the potential to do harm by yielding results that can give rise to spurious conclusions. It does not meet the standards of research that the Cass Report recommended.
I do not support flawed research, which this trial would be, and am fearful of the harm it will do to children. Look at the data we already have, first.
I entirely share the view that the trial is scientifically unsound and dangerous.
Risk/benefit is very questionable – likely only to be for a perceived aesthetic improvement/transient mood improvement at the huge expense of potential fertility/sexual function. Other options should be explored first.
Historical data showed high desistance after puberty progressed normally, with a high percentage of ultimately cis gender homosexual children. The implementation of puberty blockers has reversed the historical high desistance rates and seems clearly to set in play an irreversible psychological pathway (even if potentially medically reversible). Defacto they do not seem to stop after ‘time to think’, they move to cross sex hormones and surgery.
I am very concerned at the irreversible damage that is being done to our children and young people by these ‘treatments’.
“Gender-affirming care” is immensely harmful, especially to children.
A strong belief that children will (continue) to irrevocably damaged by these treatments, which evidentially unsound and based upon false ideologies.
As a mental health clinician with over 30 years experience across the full age spectrum, I am opposed to so called “gender affirming care.” Multiple systematic reviews support this view and highlight the harm caused by medical intervention, including puberty blockers.
Believe Hilary Cass was strong-armed into suggesting this dangerous, unjustified trial
This trial will cause significant harm to those participating in the trial.
Concern about irreversible consequences psychologically and physically
Concern about potential permanent damage to children when the data on outcomes for those who have already received the medication have not been analysed.
concern about the potential for longterm harm for these children
Concern that children will be harmed by an ill thought through clinical trial
Expected benefits of the trial do not outweigh the risks and there are significant risks to child development.
I am concerned with the affirmation model, the poor evidence and the risk of harm and short term follow up
I believe interfering with young people’s bodies is harmful both physically and psychologically.
I have grave concern about the lack of evidence and harm caused by these interventions. Both 1) the etiology, or etiologies, of gender dysphoria and 2) its natural history should be better understood before interventions with known harms, and that are already known to not help, are studied further.
It is harmful to vulnerable children
Secondly, we already have a huge data set of previous patients from gender clinics, including detransitioners such as Keira Bell – there is no need to damage further children when we can simply analyse the existing data. “
Opposition to political weakness & dangerous decisions involving children & sick science
Potential to cause irreversible harm to children and their development.
Protecting children from physical and mental damage
Protecting our children (from harmful treatments)
Safeguarding vulnerable children from unsafe and unjustifiable experimentation
Significant safety concerns around any trial that involves halting puberty, evidence base of seeing very distressed adults and adolescents post gender reassignment treatment presenting to emergency departments with self harm and suicidal ideation
The letter above outlines a number of methodological concerns. For me, the use of a waiting list control is the biggest design problem. Wait list controls are a fundamentally flawed trial design. They are well known to suppress recovery and in so doing harm participants and exaggerate apparent treatment effects. A clinical trial with this design cannot settle debates about the efficacy of the intervention. As the study design cannot answer the research question the risk to participants cannot be justified.
The puberty blockers trial will do harm and not provide the requisite knowledge. The questionnaire the children and young people are required to answer is clearly an activist one. The cohort that needs exploring is the one who attended the Gids at Tavistock Clinic
The risks of this trial outweigh the benefits for the reasons given in the letter.
The trial is not scientifically sound. It will not yield valid results and will subject children to potential harm.
The trials are unsafe
There are potential risks and before this trial is done, these risks should be evaluated by doing a retrospective study of patients who have already received this treatment
There is enough evidence of harm already.
This trial is unnecessary, harmful and ill constructed. There is already a wealth of evidence on the harms and risks of puberty blockers and no clinical rationale for prescribing them to children with normal sexual development
To stop the damage done by gender ideology in the society.
Unsafe use of puberty blockers in children
Validity of this trial. Unsafe. Most of the trial participants will be same sex attracted child as well as those on the autistic spectrum and anxiety disorders. I am extremely concerned. As a teacher of 35years I witnessed adolescent behaviour and the anxieties they had. I can understand why “Gender Ideology” is attractive to these children.
Child protection
“Gender” is not a thing. There are two sexes ONLY. To castrate, mutilate, sterilise and poison children is not science. You will be held to account for the outcome.
A former “trans child” who grew up to be a gay man
I am also a husband, father and grandfather who believes strongly in protecting all children, giving them the most appropriate medical/psychological treatments they deserve.
Child protection and safeguarding
Children can be prone to unreasonable influence by various sources even if deemed competant resulting in decisions that could potentially have an impact on the rest of their lives.
Child development & safeguarding is being ignored.
Concern about child health
Concern about vulnerable young people
Concern for young children’s development particularly those with ASD
Deep concern for children’s wellbeing
Experience of gender dysphoria in patients with Autistic Spectrum Disorder and some victims of sexual abuse in childhood.
Fundamentally disagree with such significant biological interference of the normal hormonal development of a child – and without them personally being able to understand the consequences of such action
Grave concern about medicating children to prevent their normal development.
I am a happy, confident 46 year old gay man. If, at the age of 10, an adult had put the idea in my head that i could be a straight girl instead of a gay boy, I would have clung to that, and quite likely become a life long medical patient. Young children need to be protected, not experimented on.
I am a lesbian and very concerned that puberty blockers effectively trans children who may grow up to be lesbian and gay.
I am deeply concerned for the health and well-being of young people who are put on a path to transition before they are of an age to know themselves. Adolescence is a time of significant change and discovery. Children and young people must be free to explore their sexuality without the influence of puberty blockers and/or cross sex hormones.
I do not want children to be experimented on
I do not want healthy children to be part of a medical experiment that is unnecessary.
Any medical intervention should have a plausible positive effect based on a conditions etiology and what is known about that condition. Puberty blockers do not meet that standard. Children and their families deserve better. “
I have treated children with gender dysphoria in the NHS
I’m very concern that debate, achieving a shared understanding and hence reaching a consensus has been shut down. I also worked in Community Child Health for many years and covered children with Special needs and know they bare a vulnerable group.
I’m very concerned about safeguarding children
It is abhorrent to conduct an experiment which gambles with children’s physical and mental health and which is not capable of providing proof that puberty blockers are safe nor that they can resolve any psychological issues.
It is using irrreversible life changing medication on children based on a delusional belief system. People should dress and behave how they want and ditch the sex stereotypes.
It’s child abuse to stop a child’s puberty. Research shows the vast majority of children outgrow any discomfort with their sex if left alone.
“My concern is firstly that starting puberty blockers is not a neutral act – it virtually guarantees that vulnerable children will continue down the path to cross sex hormones and lifelong health problems, whereas with counselling, and allowing normal puberty to proceed, over 80% of so called transgender children will desist. The vast majority are simply gay, autistic, both, or have a troubled history of child abuse.
No child in distress or confusion should be given iatrogenic drugs
No child should have their body mutilated.
Profound concern for safety and well-being of vulnerable children and families from the adverse effects of yet another bad medical experiment that does not accord with sensibly developed research requirements
Protection of children
Puberty Blockers are not a safe treatment even for precocious puberty, but to use for a condition that is mostly a mental health condition or a child reacting to social media or even a normal rebellious child reaction is not a good reason for wrecking a child’s life and future happiness.
Saving children from making a huge mistake.
Standing against child abuse/ experimenting on children
Stop the abuse of vulnerable children by the state
The Children Act always expects us to put the interests of children at the centre of all our interventions.
This form of eugenics is so wrong for the person and child
This is child abuse
To protect children being experimented on because they like certain hair styles or clothes.
To protect CYP
To support the pause in this experiment on children.
Trans ideology is damaging vulnerable children.
We should not be experimenting on children.
Working with vulnerable young people
Ethics
Academic rigour and ethical standards not adequate in proposed study
As a specialist in embodiment and identity, I believe the proposed trial is ill thought through, dangerous and unethical. I have already communicated my views with detailed evidence to my MP Monica Harding with a request to share it with you.
Concern with puberty blockers being used unethically
Concerns about harms to children from an ethical and a scientific point of view
Ethical, safe practice and safeguarding should be the cornerstones of our work with children.
First do no harm
First do no harm.
I agree with all the points in this letter; the trial is unethical, unscientific and ideologically driven
I believe there is no good reason to risk harm to more individual children as there have been over 2000 given puberty blockers and their health and outcomes has not been investigated. The data must be supplied on these children. There are real harms to children, many irreversible from puberty blockers. This trial is unsound and has unsound reasoning behind it. Where is the long term data on those already subjected to puberty blockers? How can you guarantee that these children will not be harmed? Statistically it is known that up to 95% of children on puberty blockers go on to the medical pathway of cross sex hormones and surgery. There is no protection for these children. They will be left sterilised with no adult sexual function. It is unethical to use these children to further justify the use of puberty blockers and the impossibility of changing your biological sex. Children need therapy not puberty blockers.
I believe this trial is unethical, unsafe, and unnecessary. I believe young children who are distressed with the sex that they are should not have the natural development of their healthy bodies disrupted by powerful drugs.
I believe this trial to be unethical and unscientific
I consider the proposed trial involving children is both unethical and unscientific.
I consider the trial to be unnecessary and unethical
I am very unhappy that for over 10 years now militant trans ideology groups have been influencing school age children (primary school age onwards) that changing their sex is simple, safe, and straight forward – with use of puberty blockers, then sex hormones, then surgery. It is not, and has created huge damage to innumerable young people. There has been bad and unevidenced practice in this area for many years now, eg Tavistock Gender Clinic, etc. This is fact that we already know, as has been documented in the Cass report and other research papers. It is polar opposite to our moral and ethical duty as adults to go ahead with this proposed further trial, which I would call experimentation, on children and the very young. The wider picture needs to be further explored, as to why there has been such an inordinately massive increase in requests to ‘change our bodies’ at such a young age.
I think this trial is unethical and unnecessary
I worked on clinical effectiveness issues for 30+ years and although I would usually support an RCT; this one would be unethical because we know that irreversible harm will be experienced by those receiving puberty blockers. Apart from the lack of an ethical case for the research there are a number of methodological flaws. The so-called “control” group are not a control at all, they are just a deferred treatment arm, and only by one year. One year is totally inadequate to allow for any meaningful difference to be detectable. Also the period of follow up is wholly inadequate – this has been one of the main factors in the paucity of evidence about puberty blockers (and cross-sex hormones for that matter) – no long term follow-up. I would think if you were to do any trial of some treatment affecting puberty, you should follow the people up well into adulthood (which you have delayed), at least until the age of 25, when current research shows that the brain is still maturing. However in young people whose development is arrested/delayed it would probably be much later – but we simply don’t know, as these treatments have been administered to children without follow up of their later development, both physical parameters and aspects of brain development and cognitive function such as verbal reasoning, memory and coordination.
It is important to protect children from unnecessary medical harm, and to keep to the principles of research ethics.
It is not ethical for children’s bodies and their future sexual function and fertility to be risked for this sort of very controversial trial, which seems to have been conceived primarily in order to financially benefit pharmaceutical companies and the clinics and doctors who would treat their peers in the future.
Medical ethics
Much concern about the proposed trial of “puberty-blockers” on children because: 1. the possibility of benefit does not outweigh likely [lifelong] risks, 2. the Tavistock experience prescribing such drugs to large numbers of children over years exists and should be evaluated before considering any new ‘trial’, 3. the dubious ethics and practical improbability for any “informed consent” undertaking for a trial involving essentially unknown outcomes with real possibility of lifelong adverse effects on development in children, 4. finally, that such a trial breaches the time-honoured and highly valued medical ethical principle “First, Do No Harm”.
Poor design. I’ve led studies through ethics and can’t understand how this was allowed.
Primum non nocere
Refusal to normalise iatrogenic harm, in the context of homophobia, misogyny and the Adultification of Children who have faced, and continue to face, innumerable insults to their development through trauma.. The design of the study is flawed, the ethics misconceived. We must stop this. The data exists. There is no justification for this political gesture of appeasement.
The first priority for research must be follow up of the thousands of children who have already taken these hormones. Only after that data is collected can a decision be taken as to whether this trial is ethical or not.
Because most children with gender dysphoria who are prescribed puberty blockers go on to cross sex hormones, these children will be exposed to irreversible changes and potentially very serious harm. There is no good evidence of benefit to mental health or as a reduction in suicide. The trial is therefore unethical. “
The trial as conceived fails too many of the established criteria for a clinical trial which would provide valid information on which future decisions could be based. I am amazed that any Ethical Committee approved it.
the trial goes against basic ethical principles and is badly designed
The trial is unethical
The trial is unethical and is not designed to give us any useful or new information. The outcomes for the 2000+ children already subjected to experimental treatment by this unlicensed drug would provide much more useful evidence.
The trial is unethical, unnecessary, not founded on any scientific understanding and harmful to children
The very fact that the trial in its present form is being contemplated reflects bias, since basic common sense, and basic ethics have seemingly been put aside.
This is a medical scandal where ideological belief is determining healthcare instead of responsible, ethical and evidence based healthcare. We do not do this in any other area of healthcare.
This is neither moral not ethical
This trial is not ethical
This trial is unethical and driven by ideology
This trial is unethical and unnecessary.
This trial is unethical. We should follow up the children who have already had puberty blockers. I feel terrible that, as a GP, one of my patients could end up in this dangerous, unethical trial.
Trial violates medical ethics, harmful experimentation on children
Trials should follow advice from the ethics committee, especially when they risk the long term health of those who can’t consent.
Consent
As a parent and support worker I am appalled that vulnerable people, vulnerable children, will be in a trial that have the potential to do irreversible harms, no child can give informed consent to this.
Because ‘gender’ distress should be treated first and foremost with sensitive emotional and psychological support rather than transformative affirmation. And no person should be set on a physical medicalisation pathway before the age of ability to understand and consent to the lifelong implications. Puberty blockers are NOT reversible.
Children cannot consent to irreversible drugs.
Children Cannot consent to participation in the trial.
Children not able to legitimately consent to a trial with life-altering consequences
Gender confusion is a state of mind, induced by many largely social factors. We should not therefore be experimenting on the healthy bodies of children, who cannot possibly give informed consent, to address this – especially when there would be lifelong negative consequences.
Grave concerns about the avoidable potential harm to healthy children; grave concerns about their ability as children to give truly informed consent
I agree with the points made above and the long term damage to these children that they cannot consent to and the complexity of the psychological difficulties many of these children have that need well funds emotional, education and psychological interventions and not drugs and surgery.
I don’t believe that it is possible for informed consent to be given to enter this trial.
I feel very anxious that children cannot consent to puberty blockers. I think also that misinformation is so widespread that both parents and children are being misled by publicly available information and it would be hard to mitigate against this phenomenon in any trial information.
I have huge concerns surrounding informed consent of the participants in this trial as well as the possible side effects of the drug to be used
I’m a parent watching in horror at what is being proposed. I have a 13 and 9 year old. There is absolutely – categorically – no way on earth that they would be mature enough to be comprehrnd or consent to the pathway treatment. Any trans children experiencing body dysphoria and distress mist be supported in a different way. Thats what boundaries are fot. Just no!!!!
No evidence consent process will be valid for these children. Long term evidence re desistance if not treated medically.
To date there is no scientific evidence to support the ‘wrong body’ narrative, nor the long-term psychological benefits of cross- sex hormones. There is, however, growing evidence for physiological harm ensuing from cross-sex hormones and disruption of puberty, and untold psychological harm (listen to the lived experience of de-transitioners). There are now many known contributory factors in gender dysphoria, none of which are explored or considered in this study: the role of autism, latent homosexuality, body dysmorphia, over-valued cognitive ideation, social influence, internalised homophobia, misogyny, sexual fetish (eg autogynophilia) and, above all, the doubts and uncertainty about gender and sexuality experienced by adolescents as a normal developmental phenomenon that has been shown to be self-resolving in the majority of cases. There is simply no need and no excuse for medical experimentation on children (who by definition cannot give consent). It may be well-intended (though the social pressure to accede to transactivist ideology is a palpable threat), but it is never the less unconscionable.
Unnecessary medical experimentation on minors, who in all legal aspects cannot consent. It is harm with long-term consequences.
Evidence/Science
As someone who has designed scientific experiments relating to a whole range of biomedical conditions – I am appalled by the design of the proposed trial for puberty blockers in children for the following reasons: 1. The experimental design does not allow for a control arm. This is inexcusable. 2. There have already been plenty of young children experimented on in this way. Why not do a meta analysis on these existing data. 3. Splitting a small cohort into two arms (neither with a control arm) will further degrade the information gathered. 4. It is well documented that a significant number of children with gender identity issues will if left to mature without medical interventions will eventually resolve and frequently grow up to be gay/lesbian/bi.
Deep concern for the implications of this study for the wellbeing of participants
Flawed reasoning and lack of evidence base for initiating this research
I want gender ideology banned from all public institutions, and for a return to evidence based practice.
Lack of evidence and poor safeguards.
Lack of long term data on outcomes into adulthood
Not evidence based
Pathways Trial is not scientifically sound
“The poor design of the trial and its short term focus means we won’t get the answers to the questions we need answers for.
This letter is relevant to my current role as a GP and as a named GP child safeguarding where we do not have enough evidence on the safety of puberty blockers
This proposed study is grotesque.
To stop the trial of puberty blockers
Trial is not necessary. Data from existing patients available and can be used.
We already have hard evidence that bone health is affected by puberty blockers, with lasting ramifications. Children are not there to be experimented on. Children need a normal puberty.
Other
Agree with the letter and it has implications for Australia.
Agreement with the case made by the letter
Agreement with the major concerns of the letter
All the strong reasons outlined in the letter.
Concern for neurodiverse grandson
Concern for young people’s physical and psychological safety, and the need for propaganda-free practice
Concerned clinician
En accord
Experience as GP, parent, SEND advocate and politician makes me extremely aware of the complexities around this issue.
Experience with teens unsure of sexuality
I agree with concerns as stated
I agree with the recommendations expressed above especially regarding the provision of open-ended counselling/psychotherapy for young people presenting with gender dysphoria
I agree with concerns in the letter
I am signing in the name of sanity, truth, goodness and reason
Regret is likely under-reported due to stigma and poor follow up, but even if it were rare it is so devastating that it really needs to be a never event!”
I feel very strongly this form of eugenics is wrong for the people it is inflicted on and society.
I hate the thought of these poor souls suffering pain and torment.
I have huge concern that because gender confusion is extremely complicated, it requires lengthy and skilled exploration to enable the to client make any decision about whether or not to go down a medical pathway.
I share the disquiet expressed in the letter
I work with young people.
I’m in agreement to the details in this letter
Member of thoughtful therapists
Normally-timed puberty is not an illness!
Puberty blockers are eugenics
Sterilising and removing sexual function from troubled teenagers is appalling.
Strength of feeling for the Subject.
The adolescent process (towards an adult identity) requires time and support; medical intervention is an assault on a natural process because there is no escape from our biology; helping troubled adolescents to learn to live with it and find pleasure in it has to be the main aim of any caring professional.
This is wrong.
This issue needs to be thought through in a proper professional manner.
To return common sense and science to medicine in this area