The Cass Review, WPATH Files, and the Perpetual Debate over Gender-Affirming Care

Julia Serano
16 min readApr 23, 2024


two children stating at a Newton’s cradle or pendulum — a device that typical sits on desktops, consisting of five metal hanging balls. when one ball is pulled sideways then released, it collides with the other balls, which forces the ball on the other side into motion, thus starting a back-and-forth chain reaction that, while not literally “perpetual,” tends to continue for a very long time.
Photo by Ron Lach at

Eleven months ago, I published Gender-Affirming Care for Trans Youth Is Neither New nor Experimental: A Timeline and Compilation of Studies. The essay documents the long history of gender-affirming care (over 100 years!) and compiles three decades worth of research studies and reviews (over 100 articles!) which together show that gender affirmative approaches to trans and gender-diverse youth are beneficial whereas gender-disaffirming approaches are harmful. I have just updated that reference list to include even more papers (most published in the last year) that further contribute to this large body of evidence.

But of course, no matter how much evidenced is amassed, there will always be some people who will continue to oppose gender-affirming care for one reason or other. A sizeable chunk of the population wants to eradicate or morally mandate trans people out of existence more generally. Others fancy themselves as skeptics who presume that trans people must be “deluded,” “brainwashed,” or following a new “trend,” despite the fact that we have always existed and are a part of natural variation. Some are parents who insist that their own child cannot possibly be trans and thus embrace any alternatives (junk science, conspiracy theories) that help them rationalize that belief.

In the final section of my essay on the anti-trans parent movement and in the intro to my spotting media bias on detransition essay, I discuss some of the unconscious biases that make many of us — even those who identify as pro-trans or neutral on the matter — suspicious of gender-affirming care. Specifically, there’s a tendency to view cis bodies as “natural” and “pure” relative to trans bodies, which are imagined to be “artificial,” “defective,” “mutilated,” and/or “corrupted” in comparison. This is why most people find it so difficult to relate to trans accounts of the dysphoria we experienced pre-transition and how much happier and healthier we are post-transition, as this runs counter to their own assessments of us. And it’s why people tend to be so alarmed by any potential irreversible effects associated with gender-affirming care, while never expressing similar levels of concern for the analogous irreversible effects that trans people experience when we are subjected to unwanted endogenous puberties.

Anyway, when the current anti-trans backlash first began to coalesce around 2015–16, much of the focus was on trans youth, who were becoming more visible precisely because social transition and gender-affirming care had finally become an option for them. Groups who coordinated this backlash pushed the following three hypotheses to explain away this apparent rise in trans youth: 1) these kids were being rushed into gender-affirming care with little to no assessment, 2) many had contracted a brand new socially contagious form of gender dysphoria, and 3) given the first two points, we must be on the brink of a massive wave of kids detransitioning.

These hypotheses are now eight to nine years old at this point, and many of the kids who were being discussed back then are now young adults. If any of these talking points were true, then by now we surely would have witnessed a large exodus of teenagers and young adults renouncing their trans identities. But that hasn’t happened. Even the most recent research studies continue to show that gender-affirming care remains highly efficacious and the rates of regret or detransition remain very low (in the 1–3% range)

Since the science is not on their side, opponents of gender-affirming care have increasingly taken to manufacturing controversy: Every month or so, there’s some new finding or study or revelation that they hold up as a “smoking gun” or “game changer.” Last year, the biggest of these was the Jamie Reed whistleblower ordeal. It centered on accusations that a Missouri gender clinic was engaging in extremely lax assessment of trans youth. While the allegations were eventually shown to be unsubstantiated and contradictory to many families’ experiences with the clinic, the story garnered a ton of media attention that ultimately led to a state-wide ban on gender-affirming care for trans youth.

In February of this year, we had the so-called “Finnish study,” which anti-trans activists touted as evidence that gender-affirming care is not lifesaving, when in fact the study showed no such thing (detailed here and here).

Then March brought us the “WPATH Files,” published by a conservative think-tank whose founder has explicitly stated that he wants to bring an end to the World Professional Association for Transgender Health (who publishes the Standards of Care, discussed in my previous essay). The 242-page WPATH Files report was a combination of leaked messages between WPATH clinicians (according to STAT News, “none of the messages offer any evidence against continuing to safely provide gender-affirming care”) and 37,000 words of editorial commentary which included “216 instances of errors, misrepresentation of data and citations, misrepresentations of the actual leaked material, and more.” While the WPATH Files were widely viewed as a non-story to those familiar with trans healthcare, it was picked up by numerous media outlets. At the time of this writing, when I search for “WPATH” on Google with a cleared-history browser, “files” comes up as the top autocomplete suggestion, and even if you don’t select that, “WPATH files” stories (several penned by anti-trans organizations) come up prominently in the results.

And now in April, we have the Cass review. There had been previous signs of anti-trans bias with the review (detailed here and here and here), so it wasn’t particularly surprising that their 388-page final report argued against social transition, puberty delay, and for severely limiting gender-affirming hormone therapy. Sociologist Ruth Pearce has compiled reactions to the report from healthcare professionals, academic experts, investigative journalists, human rights groups, and trans community organizations — feel free to consult those for more details. (Note: also detailed in a recent Mother Jones article.) Here, I will briefly highlight two of the main criticisms. First, the Cass review deemed most studies that show gender-affirming care to be beneficial as not “high quality” and thus constituting “insufficient evidence” (see e.g., Taylor et al., 2024a, 2024b, further explained here). I discuss this common tactic to discount gender-affirming approaches in my previous essay; for more on this point, see Ashley et al. (2023).

Second, in their review of the UK NHS Gender Identity Service, the Cass report found no evidence of kids being rushed into gender-affirming care with little to no assessment: According to their key findings on p.337 of the PDF, only “27% of patients were referred to endocrinology” with an “average of 6.7 appointments prior to referral”). Furthermore, out of 3306 patients, they reported that <10 detransitioned (p.341) — that’s less than a 0.3% detransition rate. While the Cass review speculates about “social contagion” and “peer influence” causing kids to become transgender, they provide no citations demonstrating that this is actually happening (btw, here’s the case against it). Most importantly, they provide zero evidence that alternative approaches — such as forcing kids to experience unwanted endogenous puberties, prolonged psychotherapy, and/or more explicit gender conversion efforts — would lead to better outcomes.

Given that the Cass review was commissioned by the NHS, it is likely to have a substantial impact on the accessibility of gender-affirming care in the UK moving forward. But it is not the “smoking gun” that anti-trans activists and trans-skeptical pundits are making it out to be. Essentially, it is just a review. In my previous essay, I cited numerous scientific reviews carried out by experts in the field which all came to a different conclusion than the Cass review: that gender-affirming care is beneficial and gender-disaffirming approaches harmful for trans and gender-diverse youth. If those reviews aren’t “authoritative” enough for you, then how about the American Academy of Pediatrics review, or the Endocrine Society review, or the WPATH Standards of Care, or any of the other health professional organizations who have come to similar conclusions.

While I believe the Cass review misrepresents the science on this matter, I can understand why it resonates with people — specifically, three different demographics of people.

Those who are largely trans-unaware likely presume that gender-affirming care is “novel” and “experimental” (and therefore suspect) simply because they had not personally heard of it until the last ten years or so. For them, the Cass report reaffirms their priors: “Finally, for the first time ever, someone has done a thorough review of this field!” If this applies to you, then you are the demographic that I tried to reach with my Gender-Affirming Care for Trans Youth Is Neither New nor Experimental essay, so I encourage you to read it. If you do, you’ll see that the gender-affirmative model arose in the early 2000s precisely because twentieth-century doctors had already tried every other alternative to no avail — this includes disaffirming kids’ genders, forcing them into unwanted endogenous puberties, perpetual psychotherapy, and more explicit gender conversion attempts. Gender-affirming care is the only thing that has positively helped trans youth thus far, and abandoning it now isn’t a passive or neutral solution — it’s an active and conscious decision to subject these children to antiquated social and medical interventions that have already been scientifically shown to be ineffective if not downright harmful.

A second demographic that embraces the Cass review (along with the WPATH Files, the Finnish study, the Jamie Reed ordeal, etc.) are people who are aware of the previous research on this matter (at least to some extent) but thoroughly distrust it. Oftentimes, these individuals gravitate toward conspiracy theories wherein gender-affirming care is merely a ruse funded and promoted by Big Pharma, or Jewish billionaires working to create a transhumanist future, or patriarchal doctors striving to replace “biological women” with “man-made women.” A more generic version of this conspiracy theory that’s very popular these days is that the gender affirmative model and all the studies supporting it are merely a product of “gender ideology.”

So what is “gender ideology” exactly? Was it invented by the healthcare industry? Or in gender studies and queer theory classes? Or by trans people themselves? Anyone with any firsthand knowledge of these groups knows that they display numerous inter- and intra-community disagreements with one another, so it’s unfathomable that they all somehow came together behind closed doors and hashed out some grand plan together.

In its general usage, “gender ideology” may refer to gender-affirming care, but also to putting pronouns in your email signature, or respecting a trans person’s identity, or recognizing gender and sexual diversity, or publicly displaying a Pride flag, and so on. Basically, “gender ideology” is an amorphous catch-all phrase for anything and everything they consider to be “pro-trans” all rolled up together into one vast conspiracy theory. (Yet somehow, cisnormativity and heteronormativity — societal-wide beliefs that are often strictly enforced — do not constitute an “ideology” in their eyes. Fancy that!)

If you believe that gender-affirming care is part of some vast conspiracy, then of course you’ll be expecting some kind of “smoking gun” to finally come along and prove that it’s all a sham, a house of cards waiting to be toppled down. To be clear, this has nothing to do with science, which is built upon large bodies of evidence accumulated over many years by multiple independent research groups all generating similar results, and thus not readily upended by a single study or review. But much like an episode of The X-Files, this imagined “smoking gun” feels “science-esque” and has the allure of “truthiness” to them.

The third demographic of people embracing the Cass review purport themselves to be objective and science-minded, but upon closer examination they exhibit clear cisnormative biases. For instance, they’ll routinely express concern about puberty delay, hormone therapy, and gender-affirming surgeries in the case of trans youth, but not when similar procedures are carried out on intersex youth, children who experience precocious puberty, or cis male teens who experience gynecomastia. They will raise concerns about irreversibility with regards to trans youth who receive gender-affirming hormones, but not when trans youth are subjected to unwanted endogenous puberties (which are just as irreversible). They will fret over the fate of children who socially transition while ignoring all the research showing that disaffirming children’s genders leads to well documented negative consequences, including depression and suicidality. They will relentlessly dissect and highlight flaws in any study that finds gender-affirming care to be efficacious, but then tout far less methodologically sound studies (e.g., the Littman paper) that suggest that the gender affirmative model may be suspect.

This may look like hypocrisy on the surface. But this third demographic’s actions are internally consistent once you realize their unspoken premise: that cisgender outcomes are inherently more healthy than transgender outcomes, regardless of what the individual in question personally experiences. A corollary to this is that children should always be pushed toward cisgender outcomes rather than transgender ones. Everything else follows from that.

There is a particular trans-skeptical pundit who immediately comes to mind here — I won’t name names (although if they sic their followers on me, I will make this paragraph more explicit and provide direct links). Circa 2016–18, they promoted the usual talking points about lax assessments, 80% desistance, detransition, and social contagion. But as these claims have not panned out over the years, they’ve resorted to moving the goalposts. Since virtually all the studies consistently show a rate of regret or detransition in the 1–3% range, this pundit is now arguing that we can’t possibly know what the rate of detransition is, implying that there’s some future wave or hidden cache of detransitioners that we simply haven’t uncovered yet. This is pure speculation, not science, but it serves their greater goal: So long as the threat of mass detransitions persists, they can depict gender-affirming care as potentially risky.

Even more troubling, this pundit is now claiming that we cannot trust trans people’s self-reports of whether we are happy post-transition — this has extraordinary ramifications given that gender incongruence and dysphoria are entirely experiential (explained further here). By this reasoning, one can discount virtually all research on gender-affirming care, along with LGB people’s experiences with sexual orientation, everyday people’s experiences with pain and depression, and so on.

Here is another example: A few years ago, on social media, a father penned a thread about his trans daughter. He described how she expressed from a very early age that she was a girl and has since lived her whole life as such. The father also mentioned that now that she was approaching puberty, they were consulting with doctors about puberty delay. In response to this, the trans-skeptical pundit posted that they didn’t believe this child should “go on blockers” because the described scenario presented “zero evidence for GD” (gender dysphoria) in their eyes. If you are familiar with this field, you’ll immediately recognize this as a classic case of gender incongruence (persistent, insistent, consistent, as they say). If “zero evidence for GD” refers to the fact that this trans girl wasn’t experiencing literal discomfort or pain, well, that’s probably because she was allowed to be herself!

The notion that this girl would somehow be better off if she was forced to go through a male puberty strikes me as unhinged. It only makes sense if you assume that being trans is merely a “mental delusion” that she (and presumably all trans people) should simply get over, and/or that cis outcomes are inherently more healthy than trans outcomes (regardless of the havoc that gender conversion efforts and unwanted puberties would wreak on a trans youth’s life).

Once you recognize this pattern, it becomes obvious that this worldview is not particular to this one trans-skeptical pundit, but can be found in many others who claim to be “science-minded” and “objective” about this matter. Take the Cass review for instance. They explicitly excluded trans people from participating in the review — in other words, our personal experiences with gender incongruence/dysphoria are not relevant to them and thus can be ignored. And their description of detransition is almost identical to the trans-skeptical pundit’s:

87. 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. [Cass report, p.33]

So does this mean that we should discourage or restrict gender-affirming care because somebody “suggested” to Cass that there’s an imagined hidden cache of detransitioners somewhere out there? Or because of a supposed lack of long-term studies? (I say “supposed” here because there have already been many studies of varying length.) And if we discourage or restrict gender-affirming care for this reason, then doesn’t this preclude us from ever obtaining said long-term data? In other words, this passage not only relies on hearsay, but it invokes circular reasoning.

Another passage from the Cass review that has garnered attention reads as follows:

16.20 For birth-registered females, the impact of testosterone will give a higher sex drive than they might have experienced during their biological puberty, and after one year will result in robust increases in muscle mass and strength (while birth-registered males will maintain their muscle strength) (Wiik et al., 2020). In the absence of any experience as an adult cis-woman, they may have no frame of reference to cause them to regret or detransition, but at the same time they may have had a different outcome without medical intervention and would not have needed to take life-long hormones. [Cass report, p. 195]

This seems to suggest that trans male/masculine youth should not take testosterone because, if they do, they will never know what it would have been like to be a cis woman (presented here as the healthier outcome: “without medical intervention”). More crucially, if they do transition sans regret or detransition, well, we can never truly know for sure whether transitioning made their lives substantially better because they don’t have the proper “frame of reference” to assess that (read: because they didn’t turn out cis, we can’t trust anything that they say about themselves). Can you see how twisted this line of thinking is? As bioethicist Florence Ashley responded, “By that logic should we force cis people to take HRT just so they can have a frame of reference for what it’s like to be trans?”

Ashley’s comment was obviously intended to illustrate a point, but let’s take their proposal seriously for a moment. What if we administered cross-sex hormones to all adolescents, just to make sure they aren’t trans. If they don’t like the effects, no worries, they can always choose to stop taking these hormones once they’re 18 (when they’re old enough to “know for sure”). After all, many “objective and science-minded” pundits have assured us that there is nothing wrong with forcing trans adolescents into unwanted puberties, so the same probably holds true for cis adolescents, shouldn’t it? And if these kids complain about the effects of this unwanted puberty — discomfort, cognitive dissonance, dysphoria — well, those are subjective feelings and we shouldn’t let them get in the way of science!

I’d imagine that this thought experiment generated visceral reactions in many readers (it certainly did for me writing it). Can you imagine the horror of being forced into the wrong puberty? Well, I can. Firsthand. Same goes for most trans people. And if you can relate to how horrific it would be for a cis adolescent to be pushed into a puberty that was abhorrent to them, what’s preventing you from extending those feelings to the trans daughter from the earlier anecdote? Or to the trans boys who Cass seems to think need to experience a cis womanhood in order to acquire a proper “frame of reference”?

I find it ironic that many of the conspiracy theorists who rant about “gender ideology” often claim that trans health practitioners and trans people like myself are attempting to “trans” other children. Sometimes they will project sexual motives onto this conspiracy theory (e.g., we are “grooming” or “sexualizing” children), but other times they act as though gender-affirming care is all part of some vague nefarious plan we are implementing (Step 1: “trans” all the children. Step 2: ?. Step 3: profit!). For the record, I don’t think that it’s possible to “create” trans kids: some kids happen to be trans but most are not. Past attempts to intentionally raise children as the other sex (which trans people had nothing to do with), by and large, failed miserably — this indicates that most cis people likely have a deep-seated gender identity too (I discuss this in more depth in this video around 26–31 minutes in).

As I’ve been saying since 2016, I believe that we should strive to minimize all unwanted irreversible changes, whether they be in cis or trans or intersex youth. I’m pretty sure that most trans people would agree with this, as would most trans health practitioners. And the gender-affirmative model — which has reliably shown a 1–3% detransition or regret rate, far lower than virtually all other medical interventions — comes far closer to achieving this than any previous approach. This does not mean that the “science is settled,” as there’s certainly more that we can learn and trans health practitioners are constantly publishing new studies (as I chronicled in my previous essay). Perhaps someday in the future, there will be an even better approach — I am open to this possibility, provided that it doesn’t involve devaluing or dismissing trans people’s experiences. But in the here and now, the only alternatives that conspiracy theorists and trans-skeptical researchers and pundits are offering are variations of the same old twentieth-century gender-disaffirming approaches that have already been shown to be harmful to trans and gender-diverse youth.

Finally, in the title of this essay, I described this debate over gender-affirming care as “perpetual.” While I wish it weren’t true, so long as this anti-trans moral panic and legislative backlash continues, I highly doubt that this issue will be satisfactorily resolved in the eyes of all parties involved. It has become politicized, much like climate change and vaccination efficacy before it. But what I sincerely hope — and the main reason why I penned this piece — is that we can finally move past the notion that this is a debate about “the science.”

If we reject all the conspiracy theorists and social conservatives who are morally opposed to trans people’s very existence, then this debate has two clear sides: Those of us who believe that the gender affirmative model is the most efficacious way to enable children to be happy and healthy while minimizing unwanted irreversible changes, and those who believe that children should always be pushed toward cisgender outcomes, no matter how much harm and unwanted irreversible effects are inflicted on trans and gender-diverse youth in the process. Some trans-skeptical pundits may reject this framing, but it’s the only way to make sense of their convoluted arguments.

This essay was made possible by my Patreon supporters — if you appreciate it, please consider supporting me there. A non-paywalled version of the same essay can also be found on Substack.



Julia Serano

writes about gender, sexuality, social justice, & science. author of Whipping Girl, Excluded, 99 Erics, & her latest: SEXED UP! more at