OPS Spotlight - The Cass Review: Distinguishing fact from fiction

By Beryl Koener, OPS member, doctor of medicine, child psychiatrist and doctor of neuropsychopharmacology

The Cass Review: Distinguishing fact from fiction

Camilla Kingdon, Nicola Stingelin-Giles & Hilary Cass

Pages 5-10 - The American Journal of Bioethics - Volume 25, 2025

Published online : 6 June 2025

https://www.tandfonline.com/doi/full/10.1080/15265161.2025.2504397

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Context

Several critiques of the Cass Review have been published since its release [1]. These have been largely refuted by multiple authors [2], who have corrected the erroneous claims found in those critiques. However, despite these corrections, new publications continue to repeat the same mistaken arguments [3].

The aim of this publication, titled “The Cass Review: Distinguishing Fact from Fiction”, is to revisit the context, methodology, and recommendations of the Cass Review, with the goal once again of correcting inaccurate claims made by its opponents—claims that not only convey biased information but also reflect inadequate interpretations of the Cass Review.

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Introduction

“The history of medicine is marked by disagreement […], yet the care of young people experiencing gender incongruence or dysphoria has been characterized by a polarized social and political debate that has overshadowed the scientific process. This has led to a neglect of the fundamental principle of evidence-based medicine, which should guide research and practice to maximize benefit and avoid harm.

Some opinions are expressed more aggressively than in any other area of clinical care, to the point that many people are afraid to voice their views; this situation is dangerous for both doctors and patients.”

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The Context of the Cass Review in the UK

The Cass Review is supported by most political parties. Its implementation began under a Conservative government and continued under the Labour government (a stark contrast to the U.S., where opinions on how to approach this area of medicine are split along partisan lines).

The Cass Review has fundamentally changed the way gender-distressed youth are cared for in the UK.

A large portion of the disinformation in the U.S. (see references above) [1] following the publication of the Cass Report stems from:

• a deep and fundamental misunderstanding of how independent reviews are commissioned and governed in the UK,

• a lack of familiarity with UK regulatory processes, and

• disregard for the stakeholder consultation process conducted by the Cass Review.

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What is an Independent Review, and How Does it Work in the UK?

• Independent reviews are used in many countries to provide objective and impartial assessments of a concerning situation or process, to ensure transparency and accountability, identify areas for improvement, and make recommendations.

• In the UK, independent reviews:

• Are typically commissioned at the national level within the NHS;

• Are established when clinical practice threatens the quality of care or patient safety;

• Are chaired by respected public figures with substantial professional experience and expertise. To ensure independence, the chair must have no connection to the specific field being reviewed (some North American critiques framed Dr. Cass’s independence from youth gender medicine as a weakness—when in fact, it is the review’s key strength);

• Respond to questions defined by the commissioning body (not by the chair, contrary to some critiques);

• Issue final recommendations:

→ which are formulated by the chair and are not pre-approved by the commissioning body or the UK government;

→ which are addressed to commissioners and service providers;

→ which are not clinical guidelines or regulations (contrary to what is suggested in some critiques of the Cass Review).

• Before being commissioned to lead an independent review, Dr. Cass was first tasked with chairing a working group conducting two systematic reviews for the National Institute for Health and Care Excellence (NICE, 2020a, 2020b) on puberty blockers (PB) and cross-sex hormones (GAH) in the treatment of children and young people with gender dysphoria.

→ When the NICE systematic reviews concluded that the available evidence was insufficient to support a policy position by the NHS England, a full independent review was commissioned.

• The Cass Report is based on 7 systematic literature reviews (Taylor, Mitchell, Hall, Heathcote, et al., 2024; Taylor, Mitchell, Hall, Langton, et al., 2024; Taylor, Hall, Heathcote, et al., 2024a, 2024b; Taylor, Hall, Langton, et al., 2024a, 2024b; Heathcote et al., 2024; Hall, Taylor, Hewitt, et al., 2024), all conducted by the University of York.

• Contrary to what the Cass Review’s critics [1,3] claim, the review also commissioned:

• an international audit of clinical practice (Hall, Taylor, Heathcote, et al., 2024),

• a qualitative study of adolescents’, young adults’, families’, and clinicians’ perspectives (Jackson-Taylor & Atkin, 2025),

• a prevalence study in primary care (Jarvis et al., 2025), and

• a linkage study to obtain long-term follow-up data into adulthood (unfortunately not completed due to adult clinics’ refusal to cooperate).

• The Cass Review also carried out a broad stakeholder consultation process (findings included in the final report):

→ Over 1,000 individuals were interviewed, including young people and adults with lived experience (direct or familial), as well as professionals working in pediatric gender medicine and broader physical and mental health and child well-being.

→ Key conclusion: Clinical professionals involved in the study stressed that gender-related distress must be viewed in a wider context. They noted a sharp rise in mental health disorders among UK youth in the past decade—particularly anxiety and depression among adolescent girls—and an increase in physical manifestations of distress such as eating disorders, tics, and body dysmorphic disorders. All of these can influence identity development and self-esteem.

→ The review concluded that this group of children and young people had been treated as exceptional, leading healthcare providers to fear applying standard assessment processes used for other distressed youth—fearing that anything less than full affirmation would label them as transphobic. As a result, many patients did not receive the same level of basic care that would have been given to other adolescents with comparable distress.

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Application of Ethical Principles in Gender Identity Services for Children and Young Adults

• Critics of the Cass Review invoke the ethical principle of patient autonomy. (However, according to Beauchamp & Childress [Beauchamp & Childress, 2019], the most cited American textbook in bioethics, autonomy does not have a higher status than other medical ethics principles like beneficence and non-maleficence.)

→ In the UK, the General Medical Council (GMC) states that a physician may only prescribe a medication if they know the patient well enough and believe the treatment meets their needs (GMC, 2021). This poses a challenge given the diagnostic uncertainty of gender dysphoria and the weak scientific evidence supporting such treatments.

→ Regarding off-label prescribing, the GMC guidelines emphasize:

• Particular attention to risks;

• That, in assessing the child’s best interest, practitioners must consider multiple factors, including which option (if multiple exist) limits future choices the least (GMC, 2007). In other words, the least invasive option should be chosen.

• Critics of the Cass Review [1,3] assess the risk/benefit balance of PB and GAH prescribing by selecting a hand-picked sample of studies (mostly rated low to very low quality in systematic reviews), while omitting the systematic reviews on the topic.

→ Such an approach would be unacceptable in any other medical field (e.g., pediatric oncology).

→ Yet the principle of informed autonomy rests precisely on providing patients with all the available information—not a selective subset chosen by the clinician.

• Critics of the Cass Review also fail to consider that the Cass Review acknowledges that medical transition may be the best option for some patients. However, it states that there is currently no reliable method to identify these youth. Instead, the Cass Review stresses the need for any such intervention to occur within a rigorously designed experimental research framework.

→ Critics invoke the ethical principle of justice to argue that restricting access to medications is unjust.

→ The authors of this article point out that true injustice lies in the fact that children and youth have received interventions based on standards and research quality inferior to those used in other pediatric fields.

• Critics claim that it would be unethical to conduct randomized controlled trials (RCTs) in this area. Yet the Cass Review never recommends RCTs as the only way to generate high-quality clinical research. It highlights instead the poor quality of existing studies (high loss to follow-up, inadequate follow-up periods, poor reporting of confounders, inadequate comparison cohorts).

• Critics also denounce the political co-optation of the issue of youth treatment.

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→ While this is unfortunately true in the U.S. at present, the same cannot be said of Scandinavia or the UK, where systematic literature reviews guide policy with broad multi-party support.

[1] A non peer-reviewed article (white paper), “An Evidence-Based Critique of the Cass Review on Gender-Affirming Care for Adolescent Gender Dysphoria” (hereafter the “Yale Critique”), was posted on Yale University Law School’s website (McNamara et al., 2024a).

·       The Yale Critique’s reference list was scanned for other papers commenting on the Cass Review, and three additional publications were identified:

o    G24 : Grijseels, D. M. (2024). Biological and psychosocial evidence in the Cass Review: A critical commentary. International Journal of Transgender Health, 1–11. https://doi.org/10.1080/26895269.2024.2362304

o    H24: Horton, C. (2024). The Cass Review: Cis-supremacy in the UK’s approach to healthcare for trans children. International Journal of Transgender Health, 1–25.https://doi.org/10.1080/26895269.2024.2328249

o    N24: Noone, C., Southgate, A., Ashman, A., Quinn, É., Comer, D., Shrewsbury, D., Ashley, F., Hartland, J., Pashdag, J., Gilmore, J., Kennedy, N., Wooley, T., Heath, R., Goulding, R., Simpson, V., Kiely, E., Coll, S., White, M., Grijseels, D. M., ... McLamore, Q. (2024). Critically appraising the Cass report. Methodological flaws and unsupported claims. https://osf.io/preprints/osf/uhndk

·       Aaron, D. G., and C. Konnoth. 2025. The future of gender- affirming care: A law and policy perspective on the Cass review. The New England Journal of Medicine 392 (6):526– 8. doi: 10.1056/NEJMp2413747.

[2]  « Critiques of the Cass Review: Fact-Checking the Peer-Reviewed and Grey Literature”

Kathleen McDeavitt, J. cohnb and Stephen B. levine

Journal of Sex & Marital therapy

2025, Vol. 51, no. 2, 175–199 https://doi.org/10.1080/0092623x.2025.2455133

·       Cheung CR, Abbruzzese E, Lockhart E, Maconochie IK, Kingdon CC. Gender medicine and the Cass Review: why medicine and the law make poor bedfellows. Arch Dis Child. 2025 Mar 19;110(4):251-255. doi: 10.1136/archdischild-2024-327994. PMID: 39401844; PMCID: PMC12013558.

[3]  Kirby, J. A. 2025. Multi-lens ethics analysis of gender-affirming care for youth with implications for practice and policy. The American Journal of Bioethics 25 (6):57–72. doi 10.1080/15265161.2025.2497983.