The Twins Who Proved Dr Cass Wrong: Understanding Gender Identity, Gender Expression, and Sexuality
A parent's message arrived in my inbox that stopped me in my tracks. Two twins, raised identically, with complete freedom to be themselves. One is a heterosexual man. The other is transgender.
A message arrived in my inbox this week that I want to share with you, because it illustrates something that I have been trying to explain for years more clearly than any research paper ever could.
A parent wrote to tell me about their 24-year-old twins, both born male. Twin 1 loved horses, wore pink clothes and pink flowery wellies, collected glass animals, had a pink bedroom, and wore mermaid pyjamas. Twin 2 loved cars and engines, wore green and blue, had a dark green bedroom with aeroplane posters, and was a Scout.
Twin 1 now lives as a heterosexual man with a long-term female partner, working in the defence industry.
Twin 2 is transgender, and came out last October. She is beginning her journey to live as her authentic self, with the full love and support of her family.
This parent put it perfectly: “So it is clear that Hilary Cass talks utter nonsense.” Both children were brought up in the same home, with the same values, with the same freedom to express themselves however they wished, with access to all kinds of toys and interests without any restriction or judgement. The only hint, the parent reflects, might have been that Twin 2 had long hair. But her dad had long hair too, so nobody gave it a second thought.
I want to use this story as an opportunity to explain three things that are often muddled together, and the muddling of which causes enormous harm to children and families who are navigating gender identity.
What Is Gender Expression?
Gender expression is simply how you present yourself to the world. It is your clothes, your hair, your make-up, your hobbies, your mannerisms, the way you walk into a room. It is entirely external and entirely visible. It can change from day to day. It can be playful or political or practical or all three at once.
Twin 1 expressed himself in a way that many people would have called “feminine.” Pink wellies, mermaid pyjamas, glass animals. And yet he grew up to be a heterosexual man, at ease in his own skin, living a fulfilling life. His gender expression in childhood told us precisely nothing about his gender identity or his sexuality. It told us that he was a child who liked what he liked, and was lucky enough to have parents who let him.
Children should be completely free to express themselves in any way they want, at any age. Playing with trucks does not make a girl masculine. Wearing pink does not make a boy feminine in any meaningful sense. Experimenting with expression is healthy, natural, and developmentally appropriate. It does not change who a child is. It does not lead them towards any particular identity or orientation. It is simply the freedom to be a child.
What Is Sexuality?
Sexuality is who you are attracted to. Like gender identity, it is internal and deeply set, though it may take time and experience to understand and articulate. You can experiment, you can explore, you can take time to work things out, but the underlying attraction is not something you choose or change.
Twin 1 is attracted to women. That is simply true of him, and it was always going to be true of him, regardless of whether he wore pink wellies or not. His sexuality has nothing to do with his gender expression in childhood, and nothing to do with his gender identity as an adult man.
What Is Gender Identity?
Gender identity is something different altogether, and this is where I want to spend the most time, because it is the most misunderstood of the three.
Let me use an image that I find helpful. Imagine a teacher says: “Can all the boys line up here, please.” Gender identity is not about wanting to be in the boys’ line. It is not about thinking the boys’ line looks more fun, or more comfortable, or more you in terms of what you are wearing or what you enjoy. It is about knowing, quietly and clearly and without any drama, that you belong there. That when the teacher called for the boys, they were calling for you.
It is the same when someone says “Can all the women put their hands up.” The women who raise their hands are not doing so because of how they are dressed, or because of who they are attracted to. They raise their hands because they identify as women. Because when society uses the word “woman,” it describes them.
Gender identity is your internal, innate sense of who you are in relation to the categories of gender that your society uses. It is not performance. It is not preference. It is not a phase or a trend or a response to social pressure. It is simply you.
And here is what is crucial: it is set. Not rigid, not fixed in every expression and detail, but set in the way that matters. You can explore it, you can learn more about it, you can find new ways to express it and live it, but you cannot deny it out of existence, and you cannot create it where it does not exist.
Where Does the “Growing Out of It” Idea Come From?
Dr Hilary Cass and others have pointed to research suggesting that many children who present at gender clinics in childhood do not persist in identifying as transgender into adulthood. This is often used to argue that we should be cautious about affirming or treating gender-questioning children, particularly adolescents, because they might simply grow out of it.
I want to be careful and honest here, because the research is real, even if the conclusions drawn from it are deeply flawed.
The older studies that showed high rates of “desistance” were largely conducted in an era when clinics accepted children with a very wide range of presentations. Many of the children included in those studies were gender-nonconforming in their expression, meaning they liked toys or clothes or activities that were not typical for their birth sex. Some had mild or inconsistent feelings about their gender. A significant number were later found to be gay or lesbian, not transgender. They had been exploring or expressing something real about themselves, just not what the clinic had initially been asked to assess.
What the research actually showed, in other words, is that gender-nonconforming expression in childhood is common, fluid, and does not reliably predict adult gender identity. Twin 1 is a perfect example of this. His pink wellies and mermaid pyjamas were never a sign that he was transgender. They were simply him, being free, in the way children should be.
What the research did not show is that children who have a deep, consistent, persistent sense that they belong in a different gender category to the one assigned at birth will simply grow out of it. Because they do not. And anyone who has listened carefully to children and families, as I have done for many years, can hear the difference.
The Difference Is Audible, If You Listen
There is a world of difference between a child who says “I like playing with trucks” or “I hate wearing dresses” or “I want to be a pirate” and a child who says “I am a boy” or “I am not a girl” or “I belong with the boys” in that quiet, settled, certain way.
One is expression. The other is identity. One is about what you enjoy and how you want to present yourself. The other is about who you are.
Good clinicians can hear this distinction. Loving parents can hear it too. Twin 2’s mother heard something in her child that she perhaps did not have a framework for at the time, but which she now understands. That long hair was perhaps one small signal among many, in a child who was navigating something profound without yet having the language for it.
Why This Matters for Treatment
The reason I am writing this post is not simply to set the record straight on definitions, important as that is. I am writing it because the confusion between expression and identity is being used, right now, to deny life-changing healthcare to adolescents who need it.
The argument goes like this: children grow out of gender nonconformity, therefore we should wait and see, therefore we should withhold puberty-suppressing medication, therefore we should allow children to go through a puberty that causes them profound distress and lasting physical changes they did not want.
Every step of that argument is flawed, and Twin 2’s story shows why. Twin 2 was not a gender-nonconforming child who was confused. Twin 2 is a transgender woman who did not yet have the words or the safety to say so. The question of whether she was allowed to wear blue or green or carry engine parts made no difference to her gender identity. It was always there. It simply waited.
To deny a young person the opportunity to have a puberty that aligns with their gender identity, on the basis that some younger children experiment freely with their expression and then settle into a cisgender identity, is not caution. It is cruelty rooted in a fundamental misunderstanding of what gender identity actually is.
What We Should Do Instead
We should allow all children the complete freedom to express themselves in any way they choose, without attaching meaning to their clothing, their toys, their hair, or their interests. We should resist the urge to read gender identity into gender expression, in either direction.
We should listen carefully when children tell us who they are. Not what they like. Not how they want to look. Who they are. And when we hear that quiet certainty, we should take it seriously.
We should support families like the one who wrote to me this week, who did everything right. Who raised their children with love and freedom, who supported Twin 2 when she came out at 23, and who are now walking alongside her as she begins the journey to her authentic self.
We should stop using flawed, outdated research to justify withholding care from young people who are suffering. The desistance studies were not about children like Twin 2. They were largely about children like Twin 1, who was never transgender, just beautifully, freely himself.
A Final Word
I wish we lived in a world where children never had to grow out of experimenting with expression. Where a boy could wear mermaid pyjamas at 40 without anyone raising an eyebrow, and a girl could be a Scout and drive a car with muddy boots without it meaning anything about her gender. I wish gender expression were completely free for all of us, at every age.
But I also know that gender identity is real, that it is separate from expression, and that it is not something anyone chooses or grows out of. Twin 2 knew, somewhere inside herself, long before the words were available to her. The pink wellies were never her story. They were her brother’s, and they were wonderful.
Both of them are exactly who they always were. And that is the whole point.
If this post has resonated with you, please share it with someone who needs to read it. And if you have your own story to tell, I would love to hear it.
Thank you, Dr. Webberley, for this nuanced and thoughtful post. I was born a transgender girl in 1940's America and, due to misunderstanding about divorce and gender identity, could not come out until I was in my sixties. I loved and economically and socially successful lives as far as the outside world knew, but lived with depression and anxiety on the inside. Something I successfully hid most of the time.
Because I had to wait before coming out and getting the gender affirming care I needed, I live with a variety of negative consequences like not having the voice I would have developed if I could have gotten puberty blockers. I've made life decisions so that I am not undermined by this outcome, but it is wrong to force this on today's youth. We should know better, and this post is an excellent example of why.