Open letter to Yvette Cooper on dangerously flawed NHS research

In May this year I was one of 85 expert signatories to an open letter to James Palmer, NHS England’s National Medical Director for Specialised Services. The letter, organised by Trans Actual, raised serious concerns about the NHS evidence reviews of hormone therapy for trans youth, the subsequent prescribing policy (i.e. a ban on NHS hormone therapy for young trans people aged under 18), and an associated public consultation.

Three months later, Palmer responded. Unfortunately, he dismissed our concerns, and outright ignored most of the evidence we presented regarding the methodological and ethical flaws in the NHS England evidence reviews.

At this stage, we have no confidence in receiving an adequate response from Palmer. My personal view is that both Palmer and NHS England as an organisation have chosen to prioritise political convenience over both good research practice and patient safety (there is a longer history to this too). Following a consultation with signatories, Trans Actual therefore took the decision to escalate the matter to the current Secretary of State for Health and Social Care, Yvette Cooper.

I have reproduced the letter below – you can also read Trans Actual’s press release and the fully-referenced, signed version sent to Cooper here.


Dear Secretary of State,

We write regarding the series of evidence reviews commissioned by NHS England into masculinising and feminising (MAF) hormones for under-18s with gender dysphoria. Based on these reviews, NHS England has consulted on a policy proposal that would make these hormones for under-18s no longer part of the clinical commissioning policy.

In May 2026, a joint letter to Professor James Palmer was signed by 85 clinicians, researchers and academics raising significant ethical, methodological, and procedural concerns with these evidence reviews and the resulting policy proposal.

In August 2026, Professor Palmer responded to our letter (attached), but a number of concerns raised were not addressed to our satisfaction.

We now write to you directly to highlight the significant issues that remain, namely: the lack of clear rationale for these reviews, the significant methodological issues and risk of bias that is evident, and lack of any plan to monitor the impact of this denial of healthcare on young trans people.

1. Lack of clear rationale

Palmer was asked to clarify the exact rationale for these 2025 under-18 evidence reviews, given that NHS England had already updated the relevant clinical commissioning policy in 2024 in response to the findings (Recommendation 8) of the Cass Review of Gender Identity Services for Children and Young People, which included the systematic evidence review of hormones for under-18s conducted by the University of York.

In his response, Palmer explained that evidence reviews are commissioned as part of standard policy development, but provided no indication of any specific impetus for reviewing this policy just one year after it had already been updated.

Following a related FOI request to your own Department of Health and Social Care (FOI-1720493), we have determined that the most likely trigger for these under-18 reviews was in fact the out-of-scope and unvalidated concerns regarding adult services raised by Baroness Cass in her May 2024 letter to John Stewart and Professor James Palmer (see also para 19.34 of the Final Cass Review).

On the basis of these unevidenced concerns, John Stewart and James Palmer decided to “define the role of gender affirming hormones through the development of a new evidence based national clinical policy which will cover all people over the age of 16.”

We note that this work was launched outside of the already-commissioned Levy Review of adult services, which did not report any such concerns regarding hormone prescribing.

In the course of developing the scope of this “all ages” national clinical policy, the Policy Working Group “deemed [it] necessary” in April 2025 to split the evidence reviews into separate children and young people (CYP) and adult policy documents, due to “the significant variation in dosage of MAF between adult and CYP populations”.

At this point, it should have been recognised that:

  • a comprehensive evidence review of CYP hormones had already been carried out as part of the Cass Review;
  • NHS England had already produced an updated CYP hormones clinical commissioning policy following that Review;
  • an ongoing living evidence review into under-18 hormones had been commissioned by NHS England and was already funded and underway.

Instead, NHS England embarked on a redundant and duplicative review of the clinical commissioning policy for MAF hormones in under-18s, overriding and ignoring both the findings and original recommendations of the Cass Review, its own 2024 CYP policy update, and the funded EPPI living review.

We are extremely concerned that Palmer was not able to give us a clear answer as to the impetus for these 2025 under-18s reviews, and that as a result of this confusion, NHS England has spent valuable time and resources duplicating and overriding work it had already commissioned and / or completed.

2. Methodological issues and risk of bias

We are further alarmed by multiple methodological decisions taken in the commissioning of the under-18s evidence reviews.

In particular, we raised in our initial letter our concerns with the decision – taken not by the independent researchers, but the policy working group – to split what is effectively two interventions in under-18s (masculinising and feminising hormones) and at most two treatment populations (those seeking masculinisation and those seeking feminisation) into 10 separate PICOs.

While we agree with the statement in Palmer’s response that Cochrane advocates for a balance between overly-narrow and overly-broad search criteria when conducting evidence reviews, Cochrane also specifically emphasises (2.5.3) that review criteria may require modification in response to initial search results, particularly when dealing with sparse data:

“The ability to address the review questions will depend on the maturity and validity of the evidence base. When few studies are identified, there will be limited opportunity to address the question through an informative synthesis. In anticipation of this scenario, review authors may build contingencies into their protocol analysis plan that specify grouping (any or multiple) PICO elements at a broader level; thus potentially enabling synthesis of a larger number of studies.”

In our view, the fact that 6 out of the 10 PICOs returned zero (0) relevant studies should have been a strong indicator that the PICOs needed to be reconsidered, and that the initial protocols had erred far too far in the direction of “splitting”.

We also note that Cochrane differentiates between (2.3.1) review PICOs, and PICOs for comparisons between interventions or groups. NHS England appears to have entirely misunderstood or ignored this distinction.

Rather than beginning with one review PICO that would naturally be broad in scope, NHS England began with ten different PICOs already limited to specific sub-treatments (masculinising vs feminising, with or without concurrent GnRH analogues) and sub-populations (male, female, non-binary) – yet we note that NHS England has not generated 10 different clinical commissioning policies, only one.

This confirms that NHS England should have commissioned a far broader initial review PICO reflecting the actual review question — namely the safety and clinical effectiveness of MAF hormones for under-18s. Instead it appears that NHS England started with 10 different review PICOs, six of which resulted in zero studies being found due to their extremely narrow scope.

This leads on to one of the most unjustifiable methodological decisions made by NHS England in these evidence reviews.

Professor Palmer’s reply to us confirms:

“The use of GnRH analogues in this cohort is not routinely commissioned in England; therefore, any hormone regimen that could be commissioned cannot be based upon evidence of people who have already been treated with GnRH analogues because the treatment effects of masculinising or feminising medicines may be different for those who have received previous treatment with
GnRH analogues.
”

Palmer uses the same justification to explain why dozens of studies that were included in the Cass-commissioned University of York evidence reviews were excluded from NHS England’s 2025 evidence reviews.

The law criminalising access to puberty blockers in England has been used by NHS England as a reason to exclude from its evidence reviews any and all international studies of masculinising and feminising hormones in which patients also received this treatment at any point prior.

This is despite the fact that puberty blockers followed by gender-affirming hormones has been a standard protocol globally for at least three decades, and as Professor Palmer himself admits: “many study populations include those who have received puberty suppression.”

We also note that, according to the March 2025 meeting minutes for the Policy Working Group, “Multiple members shared concerns raised of only having masculinising and feminising medicines (MAF) rather than the usual PSH [puberty suppressing hormones].” These concerns were seemingly overruled.

Adopting this bizarre exclusion criterion, based entirely on NHS England’s own unique and controversial policy position, inevitably led to the finding that there was a “lack of evidence” for masculinising and feminising hormones for under-18s, because so many studies were excluded.

All of this contributes to the exaggerated conclusion that there is an extreme lack of evidence regarding the use of MAF hormones in under-18s. This overstated scarcity has then been leveraged by NHS England to advocate for the removal of this aspect of gender-affirming care.

3. The appropriate response to “lack of evidence.”

Even setting aside the inconsistent rationale and significant methodological flaws we have highlighted above, there is the even more critical issue of how the purported “lack of evidence” is being used to justify the outright denial of care to trans people.

According to meeting minutes from 22nd January 2025, members of the Policy Working Group were assured that “in the absence of evidence, it is possible for specific policy areas to be informed by evidence-based decisions.” Despite this assurance, the proposed withdrawal of under-18 hormones appears to have been based solely on “absence of evidence” and, further, did not follow best practice approaches to evidence-based decision making.

We highlight statements from the BMA’s evaluation of the Cass Review regarding how evidential uncertainty is interpreted and actioned. While their points are in reference to the provision of puberty blockers, we believe they apply equally, if not more so, to the provision of under-18 hormones:

“The evidence base is limited and uncertain, with signals of both benefit and harm … A precautionary approach is consistent with this uncertainty. However, precaution in medicine typically involves risk mitigation alongside maintenance of care, rather than withdrawal of … treatment. … Alternative approaches (e.g. continued access with safeguards) are also consistent with the same evidence base.”

Instead of the precautionary approach and continued access originally recommended by Cass and adopted by NHS England on the basis of robust research, NHS England have now – for no good reason – overridden this, and are once again proposing a blanket withdrawal of treatment for trans people.

We also note that they are proposing to do so before any plans have been offered to monitor or mitigate the impact of treatment withdrawal, or develop any alternative systems of care.

4. Impacts of Treatment Withdrawal

In response to our concerns about the impact of treatment withdrawal, Palmer’s reply takes no account of patients currently on waiting lists or planning to seek referral to gender services in the hope or expectation that this might provide access to gender-affirming hormones.

As NHS England’s own Equality and Health Equalities Impact Assessment for this policy update makes clear:

“Patients who are already under the care of the NHS Children and Young People’s Gender Service and who have previously been advised that they would be referred for consideration of MAF hormones – but whose eligibility has yet to be clinically determined under the current policy – would no longer be eligible. This would mean that an existing aspiration for treatment will no longer be available for some individuals.”

The EIA also states that:

“Some stakeholder groups have previously suggested that withholding MAF hormones will lead to an increase in emotional and psychological distress, leading to risk-taking behaviour amongst children and adolescents.”

We remain extremely concerned about NHS England’s lack of articulated plans for monitoring the effect and impact of the proposed withdrawal of MAF hormones on young trans people.

Instead they have made the bizarre claim that “adoption of the policy [removing access to hormones] would in itself be a risk mitigation measure” “because of a lack of sufficient evidence relating to the safety and clinical effectiveness of MAF hormones for children and young people with gender dysphoria.”

In other words, without evidence, NHS England has adopted the blanket assumption that hormone treatments for under-18s are harmful, and therefore that the very act of denying this care reduces “risk”.

5. PATHWAYS Trial

We also note that if the decision is made to withdraw gender affirming hormones for under 18s from routine clinical commissioning, this will inevitably raise significant issues for the PATHWAYS (puberty blocker) research trial that is already underway.

The inability for young transgender patients to transfer onto cross-sex hormones with a reasonable time scale after beginning puberty blockers has already been a significant question raised in discussions of the ethical viability of this trial.

To date, we have been given no assurances as to how these issues will be addressed.

6. Expert statements

On reading Palmer’s response to our letter, Simona Giordano, a Professor of Bioethics at University of Manchester Law School, responded:

“One of the major concerns raised in our letter was that NHS England adopted review criteria that excluded a substantial proportion of the existing literature. In doing so, it risks repeating a longstanding methodological error in this field: attempting to separate the effects of puberty suppression and gender-affirming hormones as though they were entirely distinct interventions. In practice, many young people received these treatments sequentially as part of a single clinical pathway. This was especially true in England, where treatment with GnRH analogues was typically a prerequisite for access to masculinising or feminising hormones. Excluding studies involving such patients removes a large and clinically important part of the evidence base and may create a misleading impression about the amount of evidence available.”

Simona notes that Palmer’s response “does not adequately engage with several of the substantive concerns raised in the original clinicians’ and researchers’ letter, particularly those regarding the rationale for commissioning a further evidence review, the methodological choices underpinning the review process, and the implications of those methodological decisions for the evidence base considered.”

Chris Noone, a lecturer at the University of Galway who also read Palmer’s response, said:

“Guidance development and evidence reviews in Poland, France, Germany, and the Netherlands have all concluded that Gender Affirming Hormones are safe and effective as part of the care provided by gender services for young people. Furthermore, a recent paper in The Lancet (Doyle & de Vries, 2026) that considers the 13 systematic reviews that exist on this topic concludes that ‘gender-affirming medical treatment for adolescents does what it is intended to do—it shapes physical gender presentation in line with the affirmed gender of the adolescent. Research also indicates that gender-affirming medical treatment for adolescents is effective in terms of stabilising and improving the primary psychological target: gender incongruence (or gender dysphoria)’.”

He concludes that “the withdrawal of this intervention (1) does not follow from the existing evidence, and (2) does not consider the evidence on the risks of withdrawing this intervention.”

7. Conclusion

Our fundamental concern is that the provision of trans healthcare, including healthcare for under-18s, continues to come under immense external pressure from anti-trans actors, as well as being influenced by individuals within public institutions who approach policy and evidence-gathering from the presumption that gender-affirming care is inherently harmful.

In light of the above, we are calling on you as Secretary of State to:

  1. Meet urgently with James Palmer to seek answers to the unresolved ethical and methodological concerns raised in this and our initial letter, and ensure that these concerns are adequately addressed before any proposed change to the provision of MAF hormones for under-18s is finalised.
  2. Meet with trans healthcare clinicians and researchers and work with NHSE to ensure that future commissioning policy changes resulting from evidence reviews – like the forthcoming evidence reviews into MAF hormones for adults – are informed by a high respect for the expertise of clinicians, the autonomy of patients to seek care that reflects their goals and preferences, and a recognition of the risk of harm to trans patients of denying gender-affirming care.

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