BMA’s Critique of Cass Review: Cass vindicated, but BMA still getting it wrong

BMA critique vindicates Cass review but questions government “overreach” – what the BMA got right and what they are still getting wrong

On 6^th May 2026, the BMJ published a news article about the BMA critique of the Cass Review with the title, ‘Puberty blockers: BMA critique vindicates Cass review but questions government “overreach”’ (1).

Journalist Rebecca Coombes explained that the BMA “task and finish” group found the evidence base for puberty suppression and gender affirming hormones to be limited and uncertain, and acknowledged the risk of osteoporosis and fertility issues.

She noted the group was divided and did not reach a conclusion on whether restricting access to puberty blockers for under 18s was justified. 

Coombes quoted the chair of the evaluation group Professor David Strain (who is also chair of the BMA Board of Science and is UK parliament’s thematic research lead for health) commenting that restrictions could have occurred through existing bodies such as NICE, and she explained the final report criticised the government for going beyond Hilary Cass’s explicit recommendations.

The BMA commissioned a professional, independent organisation to re-analyse the Tayor systematic reviews commissioned by Cass. The BMA accepted its findings that the Taylor systematic reviews did not miss or exclude any high-quality studies or show any evidence of bias in how studies were rated or synthesised. On that basis the BMA expressed confidence in the methodology of the Cass Review and dropped its previous criticisms.

But questions remain regarding other claims made by the BMA that are discussed in the BMJ article.

• Firstly, is the BMA right that there has been government overreach beyond what was intended by the Cass Review? We argue that in fact, normal medicines safety processes were followed, which also followed the advice of the Cass Review.

• Secondly, is the BMA report right to remain undecided on the question of puberty blocker prescribing, due to claims that uncertainty of benefit and harm is equally balanced?  We argue that in fact, there is stronger evidence of harm which outweighs the uncertain benefits.

No government overreach – normal medicines safety processes have been followed including following advice from the Cass Review

The Cass Review final report is clear that the Review gave NHSE advice to restrict NHS puberty blocker use to research protocols (2, p196 paragraph 16.38).  The BMA claim that the restriction of puberty blocker prescribing is not an explicit Cass Review recommendation is therefore false.  NHSE then acted on this advice via a change in NHS policy (3).

As explained in the BMJ article, the government then followed recommendations from the Commission on Human Medicines (CHM) to close a loophole that would have allowed private prescribing to continue even though NHS prescribing was restricted for safety reasons (4). The CHM provides independent expert advice to the government about the safety and status of medicines.  This is normal process, not overreach.  Their job was to take the Cass Review findings into account along with other evidence.

The CHM is made up of senior medical professionals, pharmacologists, and lay/patient representatives. They gave clear reasons for recommending a legal ban rather than lesser measures – due to evidence of an unsafe prescribing environment (5).   They saw “evidence that raised clear safety risks to children and young people, including poor medical and prescribing practice that did not fulfil expectations for consent, safe prescribing practice or clinical practice as set out in General Medical Council (GMC) guidance”. 

The CHM also note in the same factsheet that ministers have asked the National Institute for Health and Care Excellence (NICE) to develop UK-wide standards for all clinicians to follow by 2027. 

We think the unsafe prescribing environment noted by the CHM goes far beyond the lack of NICE guidelines, as it involves a wider cultural environment of a certain way of thinking about gender distress with social suppression of alterative paradigms.  This in turn has influenced medical and research institutions and particularly the culture within specialist gender services.   

Stronger evidence of harms means puberty blockers and hormones should be restricted – why did the BMA report remain neutral?

Regarding the balance of benefits and harms, we don’t think the BMA should have concluded there is symmetrical uncertainty, and this has serious implications not only for policy and research development but also for patient safety and the reputation of the BMA.

It is wrong to give special weight to potential mental health risks if puberty blockers are not prescribed. We have national longitudinal cohort evidence from Finland that gender dysphoria does not appear to be predictive of all-cause nor suicide mortality when psychiatric treatment history is accounted for. This means it is of utmost importance to identify and appropriately treat mental disorders (6). Other research from the same cohort concluded that psychiatric needs do not subside after medical gender reassignment (7).

Prof Louis Appleby has also challenged misinformation about suicide and irresponsible reporting in this area in his independent government report (8).

Additionally, there are significant concerns about known and potential harms around the use of puberty blockers and hormones.  In the Taylor systematic reviews (9,10), it was found bone health and height may be compromised and cognitive development was identified as a key area of uncertainty.  There is some evidence of a detrimental impact of pubertal suppression on IQ in children (11).

In addition, there are known side effects from the summary of product characteristics, from the yellow card system and studies of the use of the drugs for other indications e.g. leuprorelin (12).

Systematic reviews may miss risks that are poorly studied in humans but flagged in animal studies such as cognitive and neurological development.  Systematic reviews cannot detect long term risks from synthesising short-term studies such as the known and predictable risks of infertility (13), known risk to adult sexual function (14), or known cardiovascular and thromboembolic risks (15).

When balanced against the lack of evidence of benefit, this means the NHSE, the CHM and the government were all correct to take action to restrict prescribing.

BMA says doctors should have autonomy to prescribe medicines that have no evidence base

On the same day as the BMJ article, David Strain also gave an interview to The Times newspaper’s health editor Eleanor Hayward.  He was quoted as saying “the Baroness has been vindicated in the way she approached the data”, and noted he praised her methodological approach, and when asked to name a single one of the Cass’s 32 recommendations which the BMA opposed he said: “I can’t”.  The Times also reported the BMA as saying it was “continuing to oppose a ban on puberty blockers for several reasons, not least because it is a threat to the autonomy of a doctor” (16).  The Times went into more detail about the division in the group, explaining that the final report outlines two separate perspectives. View A supported restrictions on puberty blockers due to “known and plausible harms” whereas View B supported keeping puberty blockers available and said “the Cass Review may over-emphasise potential harms and under-represent potential benefits”.

The BMA’s position attracted criticism on social media, including from the journalist Sonia Sodha who called it “inconsistent” to accept the lack of benefit and risks of harm but to insist doctors should be able to prescribe anyway.  Other posters expressed concern about the idea of “doctor autonomy” being able to override safety issues.

We think the events that have happened in the field of paediatric gender medicine have exposed many medical and research safeguards to be inadequate in the face of a genuine threat to the safety of children. This includes the flawed processes involved in developing and signing off the PATHWAYS interventional trial, which is now paused; many clinicians question the ethics of an interventional trial based on the current risk-benefit balance, the lack of a clear rationale and trial design issues (17).

Why did the BMA review and discuss the evidence but fail to reach a conclusion on prescribing of puberty blockers?  Perhaps they failed to take account of the role and medical membership of the CHM – this was a clinically driven recommendation by doctors and academics and not a decision made by politicians.  Perhaps they have too much faith in the ability of doctors to decline to prescribe in the current environment.  Perhaps the group was simply too unbalanced from the start – members with View A (in favour of restriction) were in the minority in the group and several BMA chief officers have publicly and strongly expressed views in line with View B.  

Another important question is why the report is not mentioned on the BMA’s own website.  The report is available but only hosted via a cdn.intelligencebank.com weblink (18) and this can only be found by looking at Rebecca Coombe’s BMJ article references.  This is reminiscent of Douglas Adams’ writing about official information being hidden in a basement toilet with a sign saying “beware of the leopard” – it implies the BMA are not keen for the report to be widely read.  Having been brave enough to put together a task and finish group that included different perspectives, it is a shame if the BMA cannot build on this by clearly standing by this work and protecting both the internal and external clinical debate.

1. Puberty blockers: BMA critique vindicates Cass review but questions government “overreach” | The BMJ
2. Cass H. Independent review of gender identity services for children and young people: final report [Internet]. London: NHS England; 2024 [cited 2026 Jun 14]. Available from: https://webarchive.nationalarchives.gov.uk/ukgwa/20250310143933/https://cass.independent-review.uk/home/publications/final-report/  
3. NHS England. Clinical policy: puberty suppressing hormones [Internet]. [cited 2026 Jun 14]. Available from: https://www.england.nhs.uk/publication/clinical-policy-puberty-suppressing-hormones/
4. UK Government. The Medicines (Gonadotrophin-Releasing Hormone Analogues) (Restrictions on Private Sales and Supplies) Order 2024, SI 2024/1319  [Internet]. 2024 [cited 2026 Jun 14]. Available from: https://www.legislation.gov.uk/uksi/2024/1319/made
5. Commission on Human Medicines report into the safety implications of proposed puberty blockers legislation: factsheet – GOV.UK
6. Ruuska S, Tuisku K, Holttinen T, Kaltiala R. All-cause and suicide mortalities among adolescents and young adults who contacted specialised gender identity services in Finland in 1996–2019: a register study. BMJ Mental Health. 2024;27:e300940. doi:10.1136/bmjment-2023-300940
7. Ruuska S, Tuisku K, Holttinen T, Kaltiala R. Psychiatric Morbidity Among Adolescents and Young Adults Who Contacted Specialised Gender Identity Services in Finland in 1996–2019: A Register Study.  Acta Paediatrica. 115, no. 7 (2026): 1545–1553. https://doi.org/10.1111/apa.70533.
8. Appleby L. Review of suicides and gender dysphoria at the Tavistock and Portman NHS Foundation Trust: independent report. London: Department of Health and Social Care. 2024 [accessed 2026 Jun 14]. Available from: https://www.gov.uk/government/publications/review-of-suicides-and-gender-dysphoria-at-the-tavistock-and-portman-nhs-foundation-trust/review-of-suicides-and-gender-dysphoria-at-the-tavistock-and-portman-nhs-foundation-trust-independent-report
9. Taylor J, Mitchell A, Hall R, et al. Interventions to suppress puberty in adolescents experiencing gender dysphoria or incongruence: a systematic review. Arch Dis Child. 2024 Oct 30;109(Suppl 2):S33-S47. doi: 10.1136/archdischild-2023-326669
10. Taylor J, Mitchell A, Hall R, et al. Masculinising and feminising hormone interventions for adolescents experiencing gender dysphoria or incongruence: a systematic review. Arch Dis Child. 2024 Oct 30;109(Suppl 2):s48-s56. doi: 10.1136/archdischild-2023-326670
11. Baxendale S. The impact of suppressing puberty on neuropsychological function: A review. Acta Paediatr. 2024 Jun;113(6):1156-1167. doi:10.1111/apa.17150
12. Electronic Medicines Compendium (emc). Prostap 3 DCS 11.25 mg powder and solvent for prolonged-release suspension for injection in prefilled syringe: Summary of Product Characteristics (SmPC) [Internet]. [cited 2026 Jun 14]. Available from: https://www.medicines.org.uk/emc/product/4651/smpc 
13. De Roo C, Tilleman K, T’Sjoen G, De Sutter P. Fertility options in transgender people. Int Rev Psychiatry. 2016;28(1):112-119. doi:10.3109/09540261.2015.1084275
14. Clayton A. Gender-affirming treatment of gender dysphoria in youth: a perfect storm environment for the placebo effect-the implications for research and clinical practice. Arch Sex Behav. 2023 Feb;52(2):483-494. doi:10.1007/s10508-022-02472-8
15. Irwig MS. Cardiovascular health in transgender people. Rev Endocr Metab Disord. 2018 Sep;19(3):243-251. doi:10.1007/s11154-018-9454-3
16. BMA drops opposition to Cass review into child gender treatment
17. Risks of Puberty Blockers in Children: A Call for Ethical Review – Clinical Advisory Network on Sex and Gender
18. BMA. Cass review: Evidence, interpretation, and implementation (paper C93 2025-26). May 2026. https://cdn.intelligencebank.com/eu/share/qMbw14/VEeb4/XeJDR/original/20260347+Cass+Review+update+document