'The evidence was disappointingly poor': The full interview with Dr. Hilary Cass

Listen: Our full hour on the 'Cass Review' and gender-affirming care for youth.

British pediatrician Dr. Hilary Cass led a highly anticipated independent scientific review of gender health services for children in England, commissioned by the National Health Service.

Now popularly known as the 'Cass Review,' it concludes for most young people, "a medical pathway will not be the best way to manage their gender-related distress.”

In this podcast exclusive, she gives On Point her first broadcast interview in the U.S.

Hilary Cass, pediatrician. Led the independent scientific review of gender health services for children in England, commissioned by Britain’s National Health Service. Former president of the Royal Society of Pediatrics and Child Health.

HILARY CASS: The quality was disappointingly poor, and there's a number of reasons for that. One of the significant reasons is that they just didn't follow up for long enough, particularly for young people who were taking masculinizing and feminizing hormones. Because it's not enough to just follow up for a couple of years.

You really want to know how people are doing in the longer term, and if they're thriving into adulthood. So that was one problem. Another problem is that many of the studies didn't take account of the fact that this is a really, what we call heterogeneous, so a mixed population of young people who were very different from each other.

And that population has changed in recent years, from predominantly birth registered boys presenting quite early, to predominantly birth registered girls presenting in the teenage years. Now, also, they have much greater complexity in their presentations, within that group are young people with autism, there are young people who may have other complex mental health issues.

And for each of those young people, you need to think about how all of those factors are going to impact on how well they do. And so you can't take the results of how somebody does if they are presenting as a child and have had consistent long-term gender incongruence from say when they were four or five.

They may not have the same response to medication as somebody who is presenting considerably later. And I think the other thing to say is that young people present, in many different ways, in how they present their gender identity. So the commonest group now, or the most rapidly growing group, rather, is young people who see themselves as non-binary.

And we have even less research on what the right approach is for those young people. So you can't put all of these young people into the same treatment group and say they're all going to respond in exactly the same way to this kind of approach.

MEGHNA CHAKRABARTI: So Dr. Cass, over the past 10 years, there's been a dramatic change in who's seeking care for their gender dysphoria. As you talked about, it's now many adolescent girls. Similarly, it seems that there has been a change in the understood definition of gender-affirming care from a decade or two ago. Can you talk about that a little bit?

CASS: Yes. So there has been a real swing to seeing gender-affirming care as being pretty much synonymous with medical care.

And that certainly doesn't have to be the case. Certainly, young adults have said to us, there are many more ways of being trans than just binary medical treatments. Conversely, it's really worth saying that just giving hormones without supporting people is not helpful. And an adult trans person said to me the other day, "If you just get the hormones, that does not make years of dysphoria go away, and you need some therapeutic support, as well."

CHAKRABARTI: Okay. More specifically, in the systematic review of studies relating to the use of puberty blockers, we should say that puberty blockers do have quite a well-established evidence base for use in some situations, right? For example, children with precocious puberty. Or there's also some adult cases where puberty blockers can be used, right?

So they are an accepted treatment for certain things.

CASS: Absolutely right. Yes. So, in the UK, they are what's called licensed in children, if you have precocious puberty. And the difference with those children is that they have hormones that are abnormally high at too early a stage, and that's what puts them into very early puberty.

And there's been extensive studies of using puberty blockers just to stop that very early puberty. And then when they restart their puberty at a later point, all the long-term studies have been very reassuring, and that's why they're licensed for that group. It's a very different thing to take a young person whose hormones are going through the normal increases that you expect to see in puberty and pausing that.

Because during puberty, all sorts of things are going on. Your brain is developing very rapidly. You're developing what's called your executive functioning, which is how you do some complex problem solving, complex judgment abilities. And you're also developing your sexuality and developing your identity.

And we just don't know what happens if you put brakes on all of that.

CHAKRABARTI: Okay. Specifically, in the review report, there's a discussion that there are claims, actually from quite well-respected bodies, including here in the United States, that providing puberty blockers as a form of treatment and care for gender questioning youth, they're prescribed as treatment, because they can alleviate gender dysphoria, they can improve mental health of young people who are genuinely suffering.

Did the systematic evidence find an evidence base for those goals or aims?

CASS: Okay, so that's a really important question, and we have to go back to how the thinking started about use of puberty blockers. As this started in the Netherlands, and a consultant who'd worked in adult gender services was seeing poor outcomes in some of her patients.

And she felt that the reason for that is that they weren't managing to pass in adult life. And when she moved to working in children's services, she reasoned that if you could stop puberty before you developed irreversible features of male puberty, dropping your voice, growing facial hair, that might help you pass in later life. And that would give you better psychological outcome.

So that was the first part of the thinking. And she had a second key thought that if you could pause puberty, it would just buy young people more time to think and to work out who they were, understand their identity. So those are the two things that she originally thought would be advantages of this treatment.

And then the Dutch went on to look at other outcomes from treating their first cohort. And as you say, the particular things they wanted to look at was, does this improve mental health, reduce distress, and also does it improve body image? Does it reduce the dysphoria? And the Dutch found that there were some improvements in mental health of those young people, but it didn't affect the dysphoria.

So in the UK, we attempted to reproduce that, using exactly the same approaches as the Dutch. And disappointingly, the team did not find improvements in mental health. In fact, some young people got worse, some got better, some got worse, and some made no changes. And that's the sort of result you might expect from a treatment that's not particularly effective for those outcomes.

It's really important to say that there may be a group of young people who do have early gender incongruence for whom this might be the right treatment, particularly that group of birth registered boys who will develop irreversible changes of male puberty. And so we in the UK have not said we're not going to do this at all, but we've said that we need to do this under a proper research protocol, to understand who might benefit.

But just to go back to the systematic reviews, the other studies that the team looked at, none of them really effectively reproduced the Dutch results of seeing robust improvements in mental health.

CHAKRABARTI: So to be clear, the report states, quote, "that the University of York concluded," and that's the group that did the review.

CASS: That's right.

CHAKRABARTI: "That there is insufficient or inconsistent evidence about the effects of puberty suppression on psychological or psychosocial health."

CASS: Correct.

CHAKRABARTI: And as you said, that doesn't mean it doesn't work for some young people, but just so that, again, people hearing this can understand, that just means that no one can really affirmatively claim that we know for sure it will help.

CASS: Yes. Yes. And we also have to think about which young people have been receiving puberty blockers. Because certainly in the UK, as time has gone on, the young people who were most likely to receive puberty blockers are most commonly aged around 15. And By 15, obviously you've gone through most of puberty.

So instead of really thinking, okay, how are we going to manage the distress that these young people are feeling, whilst they're making a decision about, in the long term, whether they go down a medical pathway, somehow, we've got locked into puberty blockers as the totemic treatment that young people feel. That if they don't get on that pathway, if they don't get onto puberty blockers, they're not going to get onto a medical pathway.

But actually, if you stop and think about it, there are many different ways in which we can manage distress and anxiety in a 15-year-old that don't involve puberty blockers. And yet we've somehow stopped short of trying those, just because puberty blockers have become so widely believed to be effective.

CHAKRABARTI: This is a really important point that's been brought up by the Cass Review. About did the focus on trying to provide medical forms of therapy, perhaps overshadow other forms of care. But so I want to read to you, this is from 2022, and this is from the United States Department of Health and Human Services Office of Population Affairs, and they stated in 2022, that quote, "Research demonstrates that gender-affirming care improves the mental health and overall well-being of gender diverse children and adolescents, because gender-affirming care encompasses many facets of health care needs and support. It has been shown to increase positive outcomes for transgender and non-binary children and adolescents." End quote.

Now I should say that they're speaking about gender-affirming care overall and not just exclusively medical treatments. But there's a gap there though between what seems to be the conclusions of the Cass Review versus that statement, which is not uncommon from the United States.

CASS: One of the things that young adults said to us, we spoke to young adults directly through the Review, and we also had some qualitative research, so some researchers talking to young adults, as well. And one of the things that they said is, I wish I'd known when I was younger that there were more ways of being trans or expressing my identity than just a binary medical pathway. And it may be that they're gender fluid.

It may be that they're nonbinary. It may be they're binary trans, but haven't medically transitioned, and equally it may be that they have gone down a medical transition path. But I think when people are younger, they often have only understood one or two options. And there's a whole range of options that are open to them. And so a lot of what the focus of our review has been on is saying what do we do to help these young people to thrive, and how do we give them the widest range of options that also don't foreclose for them.

CHAKRABARTI: I just want to recap. So that the systematic review found that there's insufficient evidence or inconclusive evidence about the effect of puberty blockers on mental and psychosocial health or in the alleviation of gender dysphoria. There's also the question of, there have been competing claims about whether puberty blockers have negative impact on a young person's bone health?

CASS: Again, those results were inconclusive, and we need to follow people up for much, much longer. I think one thing is important to say about the physical side effects of treatment, whether it's on bone health, or whether there may be long term cancer risks or any of those things.

And that is that for somebody who is going to go on and have an enduring trans identity, to some degree, the physical costs of treatment are almost a very small, are outweighed by the fact that there is no other way for them to live a life that manages that dysphoria that they've experienced. So the tricky thing for children and young people is not knowing which young people are going to go on and have an enduring trans identity. So I think you have to weigh those physical side effects with that in mind.

CHAKRABARTI: Okay, so you've said several times that it's tricky, if not impossible, to know which young people will go on to have an enduring trans identity. But the review also finds that the vast majority of young people who did begin puberty suppression went on to having cross sex hormones treatment. From some perspectives, that might show the success of the puberty blockers, that the children who identified as trans and then began puberty suppression, did so correctly, because then the next step was cross sex hormones.

CASS: Yeah, and that's one of the really tricky questions to understand. Because we need to view this in the broader context of what's happening to adolescents and adolescent girls in particular, across most English speaking, most of the English-speaking world. And they do have higher rates of anxiety, of depression, of self-harm, of suicidal ideation, of distress about body image. But if in the early part of your puberty, from those multiple reasons, you feel a level of distress and discomfort with your body and your identity and yourself, and you feel socially isolated and you're not meeting what's deemed to be social norms, and you then go onto puberty blockers.

Then you go through an extended period where you haven't got the typical hormone surges that might be part of working out your sexual identity, your personal identity, and so on. And then you go on to Testosterone, which is a powerful hormone, and which will give you a strong libido and start to masculinize you.

That may be absolutely the right decision, but conversely, you have very little experience of your own puberty. And probably very little basis on which you might change your mind, because you feel good on your testosterone. We have absolutely no way of knowing whether we have changed the trajectory for those young people, it's a huge unknown.

And so the more we can let young people go through their typical puberty, and work out their identity and leave their options open, as long as possible, the more likely it is that they will make the best possible decision.

CHAKRABARTI: So Dr. Cass, one thing that the review notes very clearly at the top, which is true both in the UK and elsewhere around the world, including the United States, is the rapid rise, and actually the exponential rise in the number of young people, adolescents in particular, seeking treatment for gender dysphoria.

In fact, you have a chart here that shows that around 2013, 2014, every year, essentially, the numbers spike up higher, and it's many more adolescent girls. What do you think, or what did the review seem to find in terms of what may be driving that rapid rise?

CASS: That's a really good question.

So we looked at what we understand about the biology, but obviously biology hasn't changed suddenly in the last 10 years. So then we tried to look at, what has changed? And one is the overall mental health of teenage girls, in particular, although boys, to some degree. Part of this is something to do with the well-being of girls, and that may also be driven by social media, by early exposure to pornography, and a whole series of other factors that are happening for girls.

It's a tough time to grow up. But secondly, a much more fluid approach to how young people see gender. They see gender much more flexibly than, say, my generation did. So for some young people, gender becomes the main anxiety for them and the way in which they focus their distress. And just as an example, a colleague of mine described a not infrequent sequence of events, which is a young person comes to clinic, a birth registered female, who's very distressed by her breasts, is identifying as male. And the first thing she may do for that young person is put them on the pill to stop their periods.

That's a much more straightforward intervention than puberty blockers. If she's binding her breasts, it's really important that she does it safely. So the nurse in the clinic will show her how to do that safely. And then often by the next visit, that young person is less anxious. They may still be choosing to identify as non-binary or using he/him pronouns, but the heat has gone out of the gender distress, and they're then able to talk about other issues.

And over time, they may go on to have a trans identity, or they may --

CHAKRABARTI: Is that in conflict with what the American Academy of Pediatrics has said, as recently as last year? They said that when a child declares their gender, quote, "We operate under the assumption that what they're telling us is their truth, and that the child's sense of reality and feeling of who they are is the navigational beacon to orient treatment around."

CASS: What's different about children and adolescents is that they are evolving and developing and how a young person feels at any point in their life is real. It's as real as it is for any adult, but I think the important thing is that young people are in a developing state, and how you feel at seven and ten and 20 may be quite different.

So people are developing, and the more they can keep their options open, the better it is, to do that if it's possible.

CHAKRABARTI: Is that why the review recommends that children not, adolescents not go on a medicalized pathway because of the mercurial or the evolving nature of that sense of self until later in life?

CASS: Yeah. So brains are developing until we are into our twenties. Now, that doesn't mean that nobody should go on hormones under the age of mid-twenties, it's that's an individual choice. And our reviews remit only went up to 18. I think all we can recommend is caution and keeping options open.

It's probably worth saying that for birth registered females, the male hormones work fast, and there are significant irreversible effects in terms of dropping your voice, developing facial hair and other effects. And so within a few months, you do have significant irreversible effects. Whereas for birth registered boys, estrogen takes longer to take effect, and the effects are easier to reverse.

And for any one person, it's just a careful decision about balancing, whether you have arrived at your final destination in terms of understanding your identity, versus keeping those options open. And that's a really personal decision that you have to take with your medical practitioner, with the best understanding that we can give young people about the risks versus the benefits.

CHAKRABARTI: So to get back to what was published in the now known as Cass Review about cross sex hormones, again, because I'm very, I'm quite focused on understanding the evidence base, right? Or lack thereof.

CASS: Sure.

CHAKRABARTI: So regarding cross sex hormones, the systematic review authors said there is a lack of high-quality research assessing the actual outcomes of cross sex hormones.

CASS: Yes, because following up for one year, or two years or three years tells you very little. We need to follow up for much longer than a year or two to know if you continue to thrive on those hormones in the longer term. And we also need to know, particularly from young adults, are those young people in relationships?

Are they getting out of the house? Are they in employment? Do they have a satisfactory sex life? What are the things that matter to them? And are they achieving those things?

CHAKRABARTI: So once again, the answer is, as far as the review goes, we don't know. There's insufficient evidence or poor-quality, studies which aren't enough to make informed guidelines for families and practitioners.

CASS: That's right.

Been quite a lot of misinformation that we discarded anything that wasn't a case-controlled study. We didn't set the bar that high. We were very happy with some good quality cohort studies, i.e. that's just where you follow up, and look at what happens to that group compared to another appropriate group.

But there were very few good quality cohort studies, and the problem is, as we said, that they didn't follow up for long enough.

CHAKRABARTI: Okay, so there's another aspect of the report in the evidence that your team examined that is very important for us to talk about. And it again relates to mental health, because by the time young people are seeking out help for gender dysphoria, they are quite distressed, right?

And as the report says, it is well established that children and young people with gender dysphoria are at increased risk of suicide. But then the report adds this, "But suicide risk appears to be comparable to other young people with a similar range of mental health and psychosocial challenges." So first of all, what's the evidence for that and why is that important to understand?

CASS: The most crucial thing we need to know is how do we address that suicide risk? And how do we know if this is down to their gender-related distress, and identifying as trans? Or is it because they also have an eating disorder, or they're depressed or they're isolated, perhaps because they're being discriminated against on the basis of sexuality, or a whole raft of other issues.

And because a majority of these young people have all of these issues, then what you need to do is compare to what the population rates are of suicidality in young people who have all of those other issues. But are not gender questioning. And that's where you find that the rates are fairly comparable.

So we can't say that it is the gender-questioning or the gender incongruence that's giving you additional suicide risk. So that's the first part. And so the second part is, does the gender-affirming treatment pathway reduce that suicidality, and thankfully, suicides are still very rare in young people. Although they're more common than we would wish, but they're not frequent events.

So it can be hard to make sense of the data, but such data as we have shows that people do commit suicide, both after they've had gender-affirming treatment, and before they've had gender-affirming treatment. And we can't detect a difference in the suicide rates before and after treatment.

CHAKRABARTI: So the systematic review then though really went, combed over all of the studies essentially that are cited when people say that gender-affirming treatment helps save lives.

I'm not, that's not an overstatement on my part because Admiral Rachel Levine, who's the Assistant Secretary for Health and Human Services in the United States, in fact, has said that gender-affirming care is quote, quite literally suicide prevention care.

So I'm sure you've heard similar things in the UK, but the review concluded that in a majority of studies that looked at a reduction in suicidality with gender-affirming treatment, found that there was, the studies report that there was a reduction. But there were problems with those studies in terms of they didn't control for the presence of those psychiatric comorbidities that you talked about. And then there was another study that showed that suicidality and self-harm decreased. But out of the 109 eligible participants, only 11 of them had actually completed the questionnaire on suicidality and self-harm.

CASS: Yeah, this is one of the things which makes this so difficult. So if you look at the abstract of that particular paper, it said there was a tendency for suicidality to reduce. Or, some words to that effect, but if such a small percentage actually completed the questionnaire, what does that mean about all those that didn't complete it?

And that is, that's just what dogs this research. And the other thing to think about is if young people are under the care of a very good service, where they're getting supportive therapy alongside the hormone treatment, it's really difficult to know what has reduced suicidality, if it is reduced, is it the hormones or is it the psychotherapy counseling, anything else that they're getting alongside of it?

So what is the important practical issue here? And that is that we have to provide holistic care for these young people. It's really key for us to, particularly in the UK, where we have got a national health system, and we will be operating in a proper networked fashion, so that there's links between local services and specialist services.

What we need to try and do is pick out young people who we think are at risk and say, what are all the things we need, to get in place to support this young person's risk? It may be helping with their eating disorder. It may be that they are in difficult family circumstances. There's a whole raft of things that we may need to think about, and it's much more important to say on an individual basis, how do we manage this person's risk, than just assuming that gender-affirming care is going to be the answer.

CHAKRABARTI: The report also cites another potential challenge is that it's not necessarily that care providers have wanted to overlook the other problems, but the focus from the beginning, whether by virtue of the medical culture, or even what the family and young person desire for themselves, has been on the gender dysphoria versus the other potential comorbidities.

CASS: It's also been that people have been nervous about seeing these young people, because there's so much toxicity in the debate and there's so little guidance and there's such poor evidence, that a lot of local practitioners have said, this is just outside my expertise and referred them straight to the specialist service.

And so they haven't had the real basic assessments that would happen for other young people who were similarly distressed. So I think it's a combination of things. It's just focusing on the dysphoria or it's actually just not seeing them at all in local services, because people think they need to go straight to the specialist service.

CHAKRABARTI: So there's another part of the review which I think many people were quite surprised by. There's a whole section on social transition. And the review concludes that it is possible that social transition can be done in childhood, and that could mean anything from appearance, pronouns, et cetera. It's quite a wide range.

But the review concludes that social transition in childhood may change the trajectory of gender identity development for children with early gender incongruence. For this reason, a more cautious approach needs to be taken for children than for adolescents. Elaborate on that, Dr. Cass.

CASS: So let's take a boy who is presenting some degree of gender incongruence in how they behave, in the clothes that they want to wear.

That may be because they're going to grow up and have a stable trans identity, but more commonly, young boys who present like that tend to grow up into gay men, and sometimes they'll grow up as cis, straight men. If you close down the possibilities too early, by the parent thinking that they're doing the best thing, and continuing to socialize them as a girl, it's possible that you have changed that trajectory of a child who may have grown up to be a gay man.

CHAKRABARTI: But we don't know, again.

CASS: We don't know. We don't know. And I think one of the things that many trans advocates have said to us is that by suggesting that is a worse outcome, you are suggesting that a cis outcome is better. And it's really important to say that a cis outcome and a trans outcome have equal value.

One should never be valued more than the other. But it is the case that if you are going to go through a medical transition, that is going to have lifetime implications in terms of being on medication, in terms of potential adverse effects on your health. So it's really important to be absolutely clear that's the right pathway for you as an individual.

So if it wasn't for the medical intervention, I think this would not be such a challenging issue for us.

CHAKRABARTI: Okay. Again, thinking of the very challenging navigation that families, and in this case, also schools have to undertake in dealing with social transition. To be clear, the report finds that there's insufficient evidence that's available to say whether social transitioning has a positive or negative impact on mental health for children, slight positive impact on adolescents.

But then it goes farther and says, social transition is an active intervention and that parents should be fully involved, and that clinical involvement should also take place, too. I think there were a lot of people who were concerned about those classifications and those recommendations, Dr. Cass.

CASS: Yeah. I think for schools, they have got a significant problem in that some members of staff will be worried that a child has spoken to them in confidence, and they may be at risk from their parents if the school staff speak to parents about it.

In the UK, certainly, our philosophy is that parents are well intentioned towards their children, unless you've got very good reasons to suspect that might not be the case. And secrets between children and their families living a different life at school from at home is challenging. A young person thrives best with the support of their family.

So our advice is that wherever possible, parent should be involved in a decision. Also, because parents may know things about the young person's history that school just don't know. Things like that they've been traumatized, that they've lost a parent, that they've gone through some kind of abusive situation, that they've had an eating disorder, and all of those things may have an impact on how that young person identifies.

And if the school isn't fully in the picture, they may make a decision that doesn't take account of really important factors. So for all those reasons, involving the parents is advisable.

CHAKRABARTI: Okay. Dr. Cass, this brings us back to where we began, and that is you and the independent review team undertook the world's largest systematic review of all of the evidence and studies related to care for gender dysphoric or gender-questioning young people.

And we've gone over some of the conclusions about lack of evidence for puberty blockers, similarly for hormones, lack of evidence to say with certainty if gender-affirming care reduces suicidality. These are very specific and concrete conclusions in terms of evidence.

It's interesting to me that I would say the world's largest and most influential body that provides guidance for trans care, the World Professional Association for Transgender Health or WPATH, in their most recent standards of care document, they said that despite the slowly growing body of evidence, the number of studies is still low, and there are few outcome studies that follow youth into adulthood.

Therefore, a systematic review regarding outcomes of treatment in adolescents is not possible. Yet, is that not what the Cass Review did? A systematic review?

CASS: Yes, and actually, so did WPATH. WPATH commissioned a systematic review from John Hopkins, which is obviously one of the most credible organizations in the U.S., but then they didn't refer to that in that part, in the youth part of their guidance. And that was one of the reasons that when our team rated the various guidelines, they rated the WPATH guidelines relatively poorly in terms of the rigor of their development process. Because there were points within the chapter on children and youth where the WPATH team suggested that there was strong evidence and there wasn't.

So there was a disconnect between the systematic review that they commissioned, and the conclusions that they reached.

CHAKRABARTI: When we talk about WPATH and their latest, their 8 standards of care, they do conclude that the evolving science has shown clinical benefit for transgender youth, who receive their gender-affirming treatments in multidisciplinary gender clinics.

And then they cite three different studies that they claim supports the assertion of clinical benefit. Okay. But the Cass Review points out that one of those studies cited was that original Dutch protocol that we talked about, that deals with a completely different cohort of young people. Then there's another study that had a one year follow up, showing actually very modest changes for young people.

And also, I think your team thought the study was too low quality and didn't even include it in your review. And then, most remarkably, the third study that WPATH cites is one that the Cass Review said, it's a study protocol and does not even include any results.

CASS: Yeah, that's right.

CHAKRABARTI: So what, given that it seems as if the Cass Review team comes away with some pretty fundamental concerns about the quality of not just WPATH's guidance, but the guidance offered by the Endocrine Society, the American Academy of Pediatrics, other medical societies in other countries around the world.

What's the common problem you see there?

CASS: Yes, so you have read this extremely carefully, probably better than most of the UK commentators. I think the problem is that there has been an echo chamber of guidelines. So one of the things that the York team did was they looked at where guidelines had followed each other, and they found that most of the guidelines, there was a circularity between the Endocrine Society, WPATH and a series of other guidelines. The ones that had not taken that approach and had really started with a clean slate were the Nordic ones, the Finish and the Swedish ones.

And I think the striking difference between those was that they said from the outset that this is a different population of young people, and their conclusions were very similar to our own.

CHAKRABARTI: Okay. Dr. Cass, it's now been a month since the independent review was first made public. And of course, there's been quite a bit of response to it.

I just want to quote some of the criticisms that have been made of the report. For example, the World Professional Association for Transgender Health that we just mentioned, they issued an email statement saying the report is, quote, "Rooted in the false premise that non-medical alternatives to care will result in less adolescence distress."

And they criticized some of the recommendations from the report, which they claim would, quote, "Severely restrict access to physical health care for gender-questioning young people." Your response to that?

CASS: We've not taken a position that any form of care is best, but what we have said is that it is important that all young people get access to evidence based, non-medical interventions that address the full range of their difficulties.

This group of young people, if they are depressed, if they're anxious, if they need an autism diagnosis, all of those things should be put in place. We don't know which young people may benefit from medical care, and we have proposed that every young person who walks through the door should be included in some kind of proper research protocol, so that we can follow them up and we can get those answers over time.

But for those young people where there is a clear, clinical view that they may benefit from treatments, they will, medical treatment. They will be given that medical treatment. But as I say, under proper research supervision, so that we don't continue in this black hole of not knowing what's best.

CHAKRABARTI: And I suppose another set of criticisms really are rooted in the fraught political activity around the issue of care for gender-questioning youth.

I know it's been quite fraught in the UK, and you know how serious it is here in the United States.

CASS: Sure.

CHAKRABARTI: So many professional associations and advocacy groups are just calling the Cass Report harmful, just flat out harmful. Because it could be used to weaponize political goals to severely restrict or even end any kind of care for gender-questioning young people. Is that a concern of yours?

CASS: It certainly was a concern that might be the case in the UK. I'm really pleased to say that in the UK, both of the main parties, the main political parties here have accepted the findings of the report and said we shouldn't be politicizing this. Because this is about trying to decide the best clinical care for young people, and it shouldn't be political.

None of this should be decided on ideological grounds from either side of the debate. It should be decided by really carefully working with young people, families, clinicians, and academics to try and pick through what is the best clinical approach. That's all that should matter here.

CHAKRABARTI: Dr. Cass, I just have two more questions for you.

One, to summarize the findings of, it's a 388-page report, but I think it can, it's fair to say that generally after this systematic review of all the available studies of different aspects of medicalized care for gender-questioning youth. The review found that when it comes to the use of puberty blockers, cross sex hormones, that there is an insufficient evidence base to make any certain claims about the efficacy of those treatments.

Dr. Cass, the report also points out though that the use of those treatments has skyrocketed, along with the increase in the number of children, female adolescents, reporting gender distress. Have you ever seen that kind of growth for a treatment method that didn't have an appropriate evidence base already?

CASS: This has been quite different from anything I have observed before in my clinical practice, and I think it has partly been driven by the availability of a treatment and partly by a series of sociocultural beliefs about how gender may be expressed and the mutability and flexibility of gender.

And that, in some, that changed belief set is positive in many ways. Because certainly if younger people have a much more flexible view of how gender can be expressed, that breaks down gender stereotypes. It maybe breaks down misogyny. There's lots that's good about that more flexible view, but it doesn't necessarily mean that you have to treat it medically.

People are really clear in the trans community that this should not be pathologized. And so I guess we have to think about, when is it the right thing to give quite significant medications, and when is gender expression just an expression, a normal expression that doesn't need to be treated in that way.

CHAKRABARTI: Does the Cass Review essentially bring an end to gender-affirming care in England?

CASS: No, But I think it just injects more caution. There was a study that came out just as we were going to press, and it demonstrated that gender non-contentedness, and they define gender non-contentedness by the question, "I want to be the other gender."

It was highest around 11 and it dropped off continuously into early twenties. And so it's not about saying there shouldn't be gender-affirming care. It's just, when is the right time to embark on that gender-affirming care? And most particularly, when is it safe to embark on the components of that care that might be hardest to reverse?

CHAKRABARTI: You write in the report that gender-questioning young people have been failed by the medical establishment, by the NHS in England. In order to recover from that failure, what does the report recommend change for the treatment of young people?

CASS: I think first and foremost, seeing them as a young person and not as somebody who is gender questioning, or with a gender problem or a gender issue.

They are a young person first. And I think one problem has been just seeing them through a gender lens. I think we need to re-empower professionals to not be afraid and to realize these are the same young people that they're seeing in their clinics with many other problems.

And in the long term, I think if young people could walk through the same door that doesn't have to be labelled gender, but is a clinic for young people to talk about a range of issues, whether it's their mental health, their sexual health, their sexuality and their gender, and they could see somebody who would really see them as a whole person and work out what the care package is that they need, then I think they would get a much better deal.

CHAKRABARTI: Dr. Cass, I just would like to read the last sentence of the review. You write, quote, "I am aware that this report would generate much discussion and that strongly held views will be expressed. While open and constructive debate is needed, I would urge everybody to remember the children and young people trying to live their lives, and the families and carers and clinicians doing their best to support them. All should be treated with compassion and respect."

For those children and families and clinicians listening to this interview now, Dr. Cass, what would you tell them? What thought would you leave them with?

CASS: I think the most important thing is keep your options open. I'd say what some of the young adults said, it's not as urgent as it feels.

Take your time. Think about all the possibilities open to you. Talk to other young people. But try not to rush.

CHAKRABARTI: Dr. Hilary Cass, she led the team that recently published the Independent Review of Gender Identity Services for Children and Young People. It's a massive report that was published at the behest of the National Health Services in England. Dr. Cass, thank you so much for joining us.

CASS: Thank you.