Even before the publication of the Cass Report, academics warned of “misleading trans health research“. There were cautions about the current political climate where trans people in general, and trans young people in particular were recognised as being heavily stigmatized and marginalized amid pervasive anti-transgender rhetoric in British and American media.
The final report of the Cass Review was published on 10 April 2024. It included several systematic reviews of scientific literature by the University of York, under Dr. Hilary Cass. She had no prior expertise in the care of transgender health for children or adults and is retired from medical practice, leaving her immune to account by professional misconduct. It garnered universal support from both main political parties in the UK who immediately vowed to implement the report’s recommendations in full.
However, criticism of the Cass report continues to grow amid a slew of professionals and academics in the UK and abroad publishing academic papers, pointing out its serious flaws and high risk of political bias. The latest 2024 Yale report found that, far from evaluating the evidence in a neutral and scientifically valid manner, the Cass report misrepresented its own data. Unlike the Cass report, the clinicians from Yale represent a team of researchers and clinicians that have “86 years of experience working with 4,800 transgender youth,” and have “published 278 peer-reviewed studies, 168 of which are related to gender-affirming care”.
“We produced this report to emphasize the Review’s key tenets, to bring the critical yet buried findings to the forefront, and to provide evidence-informed critiques where merited. The transparency and expertise of our group starkly contrast with the Review’s authors. Most of the [Cass] Review’s known contributors have neither research nor clinical experience in transgender healthcare.”
They say that while the Cass Review deeply considers the risk of providing medical care to those who are not transgender, it fails to consider the tansgender youth who are denied care in the process. Those transgender young people are left to “undergo permanent, distressing physical changes when they do not receive timely care”.
The Cass Review asserted that :
“the percentage of people treated with hormones who subsequently detransition remains unknown due to the lack of long-term follow-up studies, although there is suggestion that numbers are increasing.”
However, an audit of 3,306 patients (available to Cass) who were discharged from the U.K. Gender Identity Service (GIDS) revealed that fewer than 10 patients transitioned back to their birth-registered gender. This represents a ‘detransition’ rate of 0.3%. The Yale report asserts that it is “exceedingly rare that an individual would later determine that they are not transgender” after receiving clinical transgender care and support. It also describes the complexity of the definition of “transitioning back”.
“A person who regrets receiving care may continue to identify as transgender; another who stops medications may not experience regret, and one who stops identifying as transgender may not regret receiving medical care,” the report says.
Dialogue from anti-trans influencers and organisations are known to repeatedly over-assert the risk of detransition and regret, with many asserting an emerging “medical scandal“. Known and disgraced anti-trans psychotherapist Robert Withers makes such hyperbolic claims, supporting terms for gender-affirming care as a“sexual lobotomy“. Although the tone here is extreme and without evidence, Cass attempts to hide the tone, by seeming reasonable but still making unevidenced claims that are anti-scientific. Politically these claims are inline with anti-trans rhetoric and fearmongering, rather than being based in actual science.
The Cass review makes claims of bias within gender-affirming clinical literature, however, it fails to substantiate them, while being blind to its own. While double standards in terms of evidence were highlighted by Noone et al (2024), the Yale report highlights the double standard of assuming that expert evidence in gender-affirming care is biased when this is not the case in any other realm of science or medicine.
“The Review incorrectly assumes that clinicians who provide and conduct research in transgender healthcare are biased. Expertise is not considered bias in any other realm of science or medicine, and it should not be here. Further, many of the Review’s authors’ identities are unknown. Transparency and trustworthiness go hand-in-hand, but many of the Review’s authors cannot be vetted for ideological and intellectual conflicts of interest.”
The Yale Review affirms that in some areas, The Cass Review makes statements which are consistent with models of gender-affirming care. It states that The Cass Review does not actually recommend a total ban on gender-affirming medical care, although politically it is being used to do so. The authors are keen to point out the limitations of the Cass Review: it is not an authoritative guideline or standard of care, nor is it an accurate restatement of the available medical evidence on the treatment of gender dysphoria.
“It is not an effective framework for enhancing clinical services for a marginalized group of people. Foremost, it is not an endorsement of a ban on medical care for transgender youth.”
The Cass Review – Damning evidence, the highlights:
However, this is about as far as The Yale Report agrees with Cass. The remaining 6 sections of the report are damning. Here is a condensed summary:
Section 2: “The Cass Review does not follow established standards for evaluating evidence and evidence quality.”
1 – The Cass Review introduces the GRADE system as the tool for academic review, but it fails to apply it, and uses terminology not in the system such as “weak” and “poor”. In effect it imitated terminology to appear to use a known academic framework but didn’t actually do so, leading reader to “draw their own conclusions, which may not be scientifically informed.
2 – The Review fixates on evidence quality to the exclusion of many other factors that are rigorously considered by the developers of clinical practice guidelines. The Yale report highlights why evidence quality is not synonymous with clinical recommendations.
3 – “The Review does not describe the positive outcomes of gender-affirming medical treatments for transgender youth, including improved body satisfaction, appearance congruence, quality of life, psychosocial functioning, and mental health, as well as reduced suicidality. It is highly unusual for a document issuing clinical recommendations to not sufficiently describe the evidence on the effects of treatment.”
4 – The Review does not consider the harms of not offering gender-affirming medical care to a young person with gender dysphoria.
5 – The Review completely disregards the expressed values and preferences of transgender youth in its most emphatic recommendation, which is to limit care to research settings that do not yet exist.
6 – The Review conducted a series of focus groups with healthcare workers of varying backgrounds, some of whom are not even clinicians.
“Of note, 34% stated that their understanding of “gender questioning children and young people” came from the public discourse and the media. Further, 32% of respondents strongly agreed or agreed with the statement “There is no such thing as a trans child.” Denying the existence of transgender people of any age is an invalid professional viewpoint. The involvement of those with such extreme viewpoints is a deeply concerning move for a document that issues recommendations on clinical care.”
7 -The Review’s fixation on “high-quality” evidence is inappropriate. In any area of medicine, the presence or absence of “high-quality evidence” alone should not be used to decide whether to offer a treatment that has been shown to be beneficial, and care in any area of medicine should not be stopped while awaiting specific study designs. Moreover, RCTs specifically are ill-suited to studying the effects of many interventions on psychological wellbeing and quality of life among transgender people.
Section 3 – The Cass Review fails to contextualize the evidence for gender-affirming care with the evidence base for other areas of pediatric medicine.
1 – In an interview, Dr. Cass said, “I can’t think of any other situation where we give life-altering treatments and don’t have enough understanding about what’s happening to those young people in adulthood.” In reality, this is common practice in paediatrics. The Yale Report gives multiple examples. Our take: As an expert in child health, it is highly unlikely that she does not know this, it is reasonable to assume, therefore, that she was lying.
2 – The Cass Review’s preoccupation with long-term data in youth gender care is a novel metric and it does not define what it considers “longterm” to mean. “It does not describe what long-term outcomes would satisfy its concerns, and does not consider evidence that has followed patients for over a decade.”
Section 4 – The Cass Review misinterprets its own data.
1 –
“One of the Review’s central points is that the UK’s rise in referrals is so dramatic that it cannot be explained by social acceptance of transgender identity. This position is repeated throughout its 388 pages and best expressed here:
“While it certainly seems to be the case that there is much greater acceptance of trans identities, particularly among younger generations, which may account for some of the increase in numbers, the exponential change in referrals over a particularly short fiveyear timeframe is very much faster than would be expected for normal evolution of acceptance of a minority group.” (p 26)
If the expectation is that referral trends conform to the “normal evolution of acceptance for a minority group,” one would expect the Review to define this concept. It does not. This is not surprising: there is no so-called normative pattern of social acceptance for a minority group.”
2 – The Cass Review misrepresented data to make it appear like there was an exponential rise, when the data did not agree:
“While there certainly is an increase in referrals, describing this increase as “exponential” is a serious error that fuels concern that the Review is too often more interested in subjective polemics than in scientific accuracy.”
3 – The Review’s referral data failed to demonstrate that of the estimated 44,000 transgender adolescents only 10% of all youth who may benefit from care have the opportunity to do so.
4 – The Review wrongly contends that gender-affirming care is rushed, careless, and common. The data from the review showed that only about 178 youth with gender dysphoria in the UK currently receive medications that pause puberty. It is difficult to see how a medication is both “routine” and only in use by 0.0024% of the adolescent population.
Section 5 – “The Cass Review levies unsupported assertions about gender identity, gender dysphoria, standard practices, and the safety of gender-affirming medical treatments, and it repeats claims that have been disproved by sound evidence.”
1 – The Cass Review’s recommendations frequently emanate from insufficiently supported assertions that have been disproven by scientific evidence. It does not consider the most likely explanation for why most youth who receive early, supportive interventions continue onto gender-affirming hormone therapy: that they are indeed transgender. Instead, it asserts that treatment causes young people to be transgender.
2 – The Cass Review’s statements about “desistance” are unsupported. The Review cites decades-old studies uncritically, even though their findings have no relationship to a contemporary understanding of gender.
3 – The Review’s statements about “regret” and “detransition” are unsupported. Rather than citing known studies from the UK and abroad, the Cass Review used “research plagued by poor methodology, heavy selection bias, and sampling from anti-transgender websites”. The Review’s own data contradicts its assertion that “The percentage of people treated with hormones who subsequently detransition remains unknown.”
4 – The Review reanimates the debunked notion of “social contagion” – “Using sound methods, no link has been found between peer influence and gender identity development“.
5 – The Review’s concerns about the cognitive effects of puberty-pausing medications are poorly evidenced and unbalanced.
“The [Cass Review’s take] on puberty-pausing medications misrepresented the evidence by failing to include this study, and also erroneously reported that “the only study [on puberty-pausing medications and cognition] showed worse executive functioning at > 1 year…”. This latter study actually showed significantly better executive functioning in those receiving gender-affirming hormones compared to puberty-pausing medications. “
6 – The Cass Review asserts that puberty-pausing medications are not beneficial to transgender youth based on the incorrect assumption that puberty blockers alone relieve gender dysphoria.
“Experts do not expect lessened gender dysphoria or increased body satisfaction with puberty-pausing medications alone, because these medications do not change the current physical characteristics of one’s body. They only prevent future changes.”
Section 6: The systematic reviews relied upon by the Cass Review have serious methodological flaws, including the omission of key findings in the extant body of literature, deviating substantially from standard practices and rife with bias.
1 – The York team used a single search strategy for all systematic reviews, which likely excluded many relevant studies in each of the specific areas. The SR team planned to appraise the quality of studies using the Mixed Methods Appraisal Tool (MMAT). However, they switched to the Newcastle-Ottawa Scale (NOS), but with several adaptations performed by the York systematic review authors. In their published SRs, they neither mention nor justify this deviation from their protocol. This is a divergence from standard practices designed to minimize bias in systematic reviews and it is not a minor one.
2 – NOS is not recommended by any leading organizations in the field of evidence-based medicine; it is not considered a gold standard or used in guideline development processes.
Using NOS, reviewers often come up with different quality appraisals. This is also called “low interobserver reliability” and is precisely why NOS is not recommended by Cochrane.
- Quality appraisal under NOS leads to a numerical score. Despite a veneer of singular objectivity, numerical scores flatten nuanced assessments and are inherently arbitrary and unreliable.
- NOS gives equal weight to all scored items equally, though the scientific importance of these items varies.
- NOS includes items that are immaterial to assessing risk of bias.
- NOS includes an item about representativeness of the study population, which pertains to generalizability of the results to a wider population. While representative samples are critical for estimating population characteristics, they are not essential for determining treatment effectiveness.
3 – The authors of the NOS scale reported not only the Cass Reviews deviation from it, but their fundamental misunderstanding of it :
“The York SR team’s error calls into question the care with which they approached their task and the thoroughness of the peer review process undertaken by its journal of publication.”
4 – The application of the ROBIS tool to the Cass review revealed high risk of bias across all domains.
5 – The York SR team’s findings and conclusions conflict. While EVERY study on gender-affirming hormone replacement therapy reported significant increases in wellbeing, the Cass Review said it did not, flying in the face of its own evidence.
6- No accepted method to determine quality of the entire body of evidence was used. Without a clear description of how the quality of the entire body of evidence was determined, the final conclusions of the York SRs lack substance.
Section 7: The Review’s relationship with and use of the York systematic reviews violate standard processes that lead to clinical recommendations in evidence-based medicine.
1 – “The Review subverted the well-established process for making clinical recommendations from systematic review findings.”
How recommendations are made using the well-established processes that lead to clinical recommendations in evidence-based medicine:
How the Cass review subverted the process:
You can read the Yale report in full here:
Further reading:
I like it when individuals come together and share thoughts.
Great site, keep it up!