The Cass Report: Anti-science and Anti-trans

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For several months now, many of you have contacted me here on YouTube or on Patreon to ask my thoughts about the “Cass Report,” the slang term for the “Independent Review of Gender Identity Services for Children and Young People” commissioned by the UK’s National Health Services in order to guide their recommendations for kids who want gender-affirming care. We colloquially call it the “Cass Report” because the lead author was Hilary Cass, a past president of the Royal College of Paediatrics and Child Health.

The report took several years to compile, and the final result was published in April of this year. The NHS used preliminary findings in the report to guide some decisions, like halting the use of puberty blockers in kids with gender dysphoria. Because surprisingly, the conclusions of this seemingly very detailed nearly 400-page report was to recommend the exact opposite of the current global standards recommended by organizations like The American Academy of Pediatrics, the American Medical Association, and every other major medical organization in the US.

Because the Cass Report recommended psychiatric care instead of medical interventions, it was largely embraced by transphobes around the world, who cited it as proof that treating kids with gender dysphoria is ultimately some kind of child abuse. And because I’ve talked in the past about the scientific basis for the current consensus that gender-affirming care is good actually, a lot of you were wondering if this report changed my mind.

I’ll be honest, when I first heard about the Cass Report, I definitely thought it was compelling. Yes, it ended up going against the existing scientific consensus, but it was coming from within the medical establishment. I always say that if you’re going to overturn established science, you’d better be working within the field you’re disrupting. Also, that scientific consensus isn’t as solidified as in other fields, like the consensus on evolution or climate change. This is relatively recent research, and while the data did all seem to lean in one direction, it’s not completely ridiculous to imagine new, better research fine tuning the consensus on how best to treat kids with gender dysphoria.

So then I read the report myself, and while it presented its findings as unbiased and not about “rolling back on people’s rights to healthcare,” that opening raised a bit of a red flag for me. Why does that even need to be said? Ah, because that’s exactly what we already know it led to.

Another red flag was that the report claims that a systematic overview found no evidence for the benefit of puberty blockers, but recommended a purely psychological approach instead, which has….no evidence of benefit. Not in this report, and not in the past few centuries of attempting to “treat” gender dysphoria with therapy. In 11.8 on page 158, the report reads:

“The University of York concluded that there is limited research evaluating outcomes of psychosocial interventions for children and adolescents experiencing gender incongruence, and low quality and inadequate reporting of the studies identified. Therefore, firm conclusions about their effects cannot be made. Identification of the core approach and outcomes for these interventions would ensure they are addressing key clinical goals, attending to the needs of children and families as well as supporting future aggregation of evidence.”

That’s far less of a recommendation than the same report’s summary of puberty blockers, which reads “In summary, there seems to be a very narrow indication for the use of puberty blockers in birth-registered males as the start of a medical transition pathway in order to stop irreversible pubertal changes. Other indications remain unproven at this time.”

Okay…so, if puberty blockers have some use cases but psychological treatment alone has none, why are we recommending the latter and banning the former? The math just ain’t mathin’ for me.

Despite these red flags, I still didn’t make a video on the report. Why? Simple: it’s not my area of expertise. I am not a doctor researching gender affirming care, and I’m not a statistical analyst who can easily look at a systematic review like this and say “Oh, they shouldn’t have used that regression,” or “they failed to properly weight these studies.” Also, not for nothin but this thing is 388 pages. I do not have the attention span to be sure I wasn’t missing something. So I cooled my heels and waited for the people who do have that expertise to weigh in. And now they have started to do so, so it’s finally time to talk about it all.

First up, way back in March I noticed The Cass Review: Cis-supremacy in the UK’s approach to healthcare for trans children by Oxford professor Cal Horton. In that piece, published in the International Journal of Transgender Health, Horton argues that the Report is blatantly biased, framed in a way that ignores transphobia and accepts that ideas like “there is no such thing as a trans child” is a “valid professional viewpoint” and not a sign of deep prejudice. That article is available online in full and I encourage you to read it – as always, links to everything I talk about are in the transcript, linked in the description box dooblydoo.

Still, that wasn’t as hardcore an investigation as I was interested in, so I was pleased to see Biological and psychosocial evidence in the Cass Review: a critical commentary, published this month in the  same journal. In this dissection, Dori M Grijseels of the Max Planck Institute for Brain Research reveals some telling mistakes that I certainly never would have caught. For instance, one large section of the report argues for the frequency of mental disorders in young people seeking care, and to support that Cass cites “[o]ne study (that) reported data separately for 2012 and 2015 and demonstrated an increase (in autism rates) from 1.8% to 15.1%.” But the study actually showed “a non-significant increase from 13.8% to 15.1%.”

That’s just one very easy to understand example out of several that Grijseels points out, in which Cass misrepresents or changes data from the studies she claims to cite.

The problems don’t end with the studies Cass cites, because as you know, systematic reviews and meta-analyses are also about what studies are NOT cited. Here’s just one example:

“In point 8.14, the Review cites Karamanis et al. (Citation2022) as a large register-based population study, to show that trans identity is mainly determined by environmental factors, rather than having a genetic basis. However, this study included only 67 twins, and as such is much smaller than the numerous other studies (Alanko et al., Citation2010; Bailey et al., Citation2000; Burri et al., Citation2011; Sasaki et al., Citation2016; Van Beijsterveldt et al., Citation2006) which did find support for heritability of trans identity. The Review does not discuss or cite any of these other studies, or explain why the Karamanis study was determined to be the most relevant. The Review argues that this study gives more credence to the idea of sex hormone exposure in the womb causing gender dysphoria. However, given the numerous contradictory findings in the literature, this single study does not provide sufficient evidence to give due credence.”

Grijseels also addresses the weighting of the studies Cass cites, and the prioritizing of certain data from those studies over other data from the same studies. For instance, in discussing four studies on suicidality, three of them found that hormone treatments reduced suicidality but Cass concluded that this evidence was too inconsistent and thus no benefit can be confirmed.

Meanwhile, the report itself claims that “Evidence to date suggests that puberty blockers neither lead to substantially reduced adult height in transgender females.” 

But just one page later, Cass concludes that blockers present this scary risk: “height gain may lag behind that seen in other adolescents.”

She consistently downplays any evidence of benefits while highlighting “risks” that aren’t actually risks.

If you read through that paper, you might get to the end and think, well, I guess the Cass Report is dead. I mean, you’d think that if you have never once interacted with the rabid anti-science transphobic mob. They’ll be propping this thing up for years, which is why I’m grateful that the actual experts on this topic are just going to keep on kicking it while it’s down. Grijseels has joined forces with an international team of doctors, psychologists, and gender and sexuality researchers, like the queer Avengers, to publish another paper, currently in preprint but available in full online, and god damn is it, well, damning.

In “Critically Appraising the Cass Report: Methodological Flaws and Unsupported Claims,” the researchers don’t just point out the biased choosing and weighing of studies and the unfounded conclusions, but they actually used the “risk of bias” tool recommended by Cochrane, the king of systematic reviews, to see if there’s an objective measure of whether or not Cass was unfairly biased against trans care.

Sure enough, they “identified a high risk of bias in each of the systematic reviews driven by unexplained protocol deviations, ambiguous eligibility criteria, inadequate study identification, and the failure to integrate consideration of these limitations into the conclusions derived from the evidence syntheses. We also identified potential sources of bias and unsubstantiated claims in the primary research that suggest a double standard in the quality of evidence produced for the Cass Report compared to quality appraisal in the systematic reviews.”

If you’re wondering why a systematic review this biased and poorly edited would be written, accepted, published, and used to guide public policy, I recommend this article from Mother Jones, published back in May, that summarizes what we now know about the making of the Cass Report.

For instance, the report fails to reveal everyone who collaborated on it, but a blogger discovered that representatives from “the Society for Evidence-Based Gender Medicine, which the Southern Poverty Law Center has dubbed “the hub” of the “anti-LGBT pseudoscience network”” were apparently members of the NHS Working Group on Gender Dysphoria. And Zinnia Jones found court documents showing that Cass herself “met with Patrick Hunter, a DeSantis appointee to the Florida Board of Medicine, member of SEGM, and big proponent of banning gender affirming medical care for transgender youth.”

“Hunter sent Cass materials from Florida’s thoroughly discredited 2022 review of gender medicine,” and then they became good buddies and weird, both of their reports ended up with the same conclusions!

I left all that info til the end of the video because I don’t want you to cry that I’m poisoning the well. The Cass Report isn’t wrong because of the fact that Cass colluded with pseudoscientific transphobes. It’s wrong because it mischaracterizes the science in a multitude of ways that actual experts have deconstructed repeatedly now. The pseudoscientific transphobic collusion is just a hint as to WHY the report ended up this way.

I’ll be interested to see if the Cass Report gets edited to fix any of the problems brought up–even the very basic ones, like deleting a “1” to turn an insignificant increase in autism rates into an extremely significant one. There’s not much they can do about the rampant bias, but a defense would certainly be interesting.

It’s a total coincidence but the last few times I’ve put out a video defending the current consensus on the treatment of children and young people with gender dysphoria, I happen to have been on vacation and away from the internet. And each time I’ve come home to find an avalanche of angry comments from frothing transphobes who crow that my not responding to them is proof that I don’t respect them, as opposed to proof that I was just not on the internet. Well, this time I don’t have a vacation planned, so I want the transphobes to know that THIS time, I’m not responding because I do not respect you in the least.

Rebecca Watson

Rebecca is a writer, speaker, YouTube personality, and unrepentant science nerd. In addition to founding and continuing to run Skepchick, she hosts Quiz-o-Tron, a monthly science-themed quiz show and podcast that pits comedians against nerds. There is an asteroid named in her honor. Twitter @rebeccawatson Mastodon Instagram @actuallyrebeccawatson TikTok @actuallyrebeccawatson YouTube @rebeccawatson BlueSky

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