'I landed into something, because of an experience I had as a kid, and I felt I couldn't look away, even though I was told to by people close to me." This is psychotherapist Stella O'Malley's response when I ask why she is so caught up in the debate around the best response to transgender children.

"If I didn't have a personal interest - if I hadn't had the experience I did, which was so visceral, at such a young age - I'd say I'd be watching the debate, I'd be interested, but I wouldn't be right in the centre of it."

The experience she refers to is the conviction she had as a child, "from as far back as I can remember; I was extraordinarily convinced 'I should be a boy so let's all just say I'm a boy.' This was 1980, so everybody just went with it. I was a strange little kid; that's how I would have been perceived by adults. It's not that I thought I was a boy - I hadn't lost touch with reality - but I thought I should be.

"It just seemed fundamentally wrong that I was a girl because I was so boyish and I was so good at being a boy. I was very dismissive of other tomboys, I thought they were very girly-boys, and I was the real thing. That was so deep and profound, from as far back as I remember. Yes, I was an unhappy kid, and particularly unhappy as an adolescent. Puberty was a train wreck. And yet ultimately, it fundamentally released me from what is now termed gender dysphoria. By the time I had moved out of puberty, I had left it completely behind."

And so she has contributed a chapter to a new book Inventing Transgender Children and Young People, a compilation of perspectives from psychiatrists, academics, social workers, social activists, parents, a de-transitioned man and more, all committed to exploring fully the many, complicated aspects of transgenderism, and what society can do in response to it. Stella's chapter Trans Kids: It's Time To Talk, details her experience of making a documentary for Channel 4 a year ago, and the hostile response to it from sections of the trans community.

"It's such a hostile, polarised environment. Anybody who speaks up gets a huge amount of public shaming and public animosity, as I did." Does she still? "I do, yes. But I also get a huge amount of support. I was contacted by an awful lot of people, some who had de-transitioned, others who were maybe 10/15 years into transitioning, who were saying 'if I had my time back, I'm not sure I would do this…' It carries a heavy burden of medical treatment. The first few years can be very joyful, but there is so much surgery and medication, for life, involved; it's a hard road."

So, back to why she is determined to speak up, and take the aggression that comes her way? "Quite apart from my personal experience, identity is fascinating because goes to the heart of who we are. It's psychologically fascinating. And this is a new issue. Anyone in my field will have read a great deal about anorexia, depression, alcoholism; we've studied these issues and learned about them. Transgenderism is a whole new concept, and it has caught hold of young people so quickly."

St Columcille's Hospital in Loughlinstown, reported a 2,100pc increase in cases of gender dysphoria in the last decade.

"Anyone who knows the history of psychology will be aware that these kinds of extraordinary bursts are generally very destructive to some people. In the 1990s there was a push on repressed memory syndrome. It was, very like this, being talked about a huge amount. In terms of numbers affected, it wasn't huge, but the stories were extreme and shocking. And it was very polarising - you were on one side or the other: 'this syndrome exists, this doesn't exist.' That debate has largely died out, apart from the odd outlier who still believes in it. But, it did a massive amount of damage to a small number of people."

And she sees parallels with the trans debate? "Yes. 'Born in the wrong body' is a great description of a feeling but it's not a diagnosis. And psychologically, that is a very dangerous thing to say to somebody. Can you be born in the wrong body? Can you be born in the wrong head? Are people who are born in very challenging bodies, through disability, are they born in the 'wrong' body? I reject the concept. We're born in the body we have. We're born in the head we have. There's a little we can do. We can make changes to our bodies with hormones and surgery, we can make changes to our heads with medication, and, for some people that works.

"But I think the underlying concept of being born in the wrong body is troubling. And for somebody who is 14, 15, maybe younger, and feeling distressed, lost, lonely, who feels wrong, and that their body is wrong - that phrase can be hugely appealing. The idea that they have an 'answer' is psychologically alluring. The fact is that some people have a condition called gender dysphoria and for some people medical transition works as a means to reduce their gender dysphoria; for others their gender dysphoria is reduced through other types of therapy and for still others the dysphoria simply vanishes with time. No one is 'born in the wrong body'."

And, if there was nothing more to the matter than that, all would undoubtedly be well. But the reality is that medical transition is a complicated, long-drawn-out and expensive process, often involving surgery, and invariably a lifetime of hormonal treatment. "The fundamental principle of medicine is 'first, do no harm,'" Stella points out.

"And that often means no intervention, certainly no surgical intervention, unless necessary. Even with very serious illnesses like cancer, doctors move slowly where they can. In therapy, it's the same idea - proceed slowly and carefully. And then you get to the issue of gender dysphoria, and intervention happens so quickly.

"And I know there are issues around the onset of puberty and what effect that has on a trans-identifying child, but this is a medical process that never stops and we need to move with care. The stakes are very high: if a child takes puberty blockers and then goes on to take cross-sex hormones they risk infertility and impaired sexual functioning for the rest of their life. There may not be a huge number of people for whom this is an issue, but where it is, the stakes are massive."

And indeed, in Inventing Transgender Children… 'Patrick', a de-transitioned man, refers to the distress of noticing that "one isn't becoming the other sex, but some kind of patchwork, with scars and implants, in a life-long medicalisation process with synthetic hormones".

Alongside the personal experience, however, Stella is also driven by a broad and deep belief: "To me, the biggest issue, by a million miles, is the silencing of debate. Experts who know their stuff, if they want to join the debate and everything about their world, their education and their qualifications suggests that they could have something to contribute - they should be allowed to debate it. But something very pernicious is happening, which is that educated people with something valuable to contribute are being closed down, and that's a very frightening world to be in, no matter what the issue is. A sign of progressive society is that we debate, discuss, argue. We permit disagreement, because after robust disagreement, one gets better solutions."

'Inventing Transgender Children and Young people', edited by Michele Moore and Heather Brunskell-Evans is out now, published by Cambridge Scholars Publishing

Sunday Independent