Media discussions about transgender people have taken on a personal significance for me. My son was my daughter until last year, when, after years of hints here and there, and months of him being uncharacteristically tearful and reclusive, he told us he was a boy.

My instinct was caution, determined to shield him from wounding words and quizzical looks and the need to navigate out of this if he was wrong. I said, “Let’s not tell anyone at school just yet. You’re only 12. I promise I believe that you believe you’re a boy right now, but what if you tell your friends and then realise you’ve made a mistake?”

I worried about boyfriends, girlfriends, online bullying and long memories. My happy child, always off exploring with hordes of kids, might be left behind, too weird to be in the gang. He was quiet, but determined, questioned how long he had to wait. I said until half-term – a few weeks away –and if you still feel the same then, I’ll talk to school about you wearing the boys’ uniform.

What I didn’t know then is that people don’t just change their minds about this. I’ve researched and researched and found nothing but evidence confirming that once a person, young or old, comes out, explains their gender isn’t all it seems, that’s that. It isn’t a mistake, a cry for help, or a mental illness – it’s a fact. And the time it most commonly comes to light is when puberty arrives. It’s all so obvious now – it wasn’t then – but the time physical difference becomes apparent is the time the distress of gender dysphoria becomes acute.

A week later, a call from school – my son, so upset he couldn’t speak, had gone to a trusted teacher. He couldn’t bear to be thought of as a girl for one more minute. He was a boy, he wanted to dress as a boy, he didn’t want a red pen cross on his Spanish homework when he’d used the masculine to describe himself. We met with his open-minded, compassionate teachers. I was still urging caution – nothing public, not yet, please, just a little more thinking time. What about peers’ reactions? We mustn’t rush. He explained, through tears, that he would rather people bullied him about being a boy than have to carry on pretending he was a girl.

And the penny dropped.

My son, in his distress, helped me realise that there is something even worse than being abused in the street, and that’s being told by strangers you’re not who you know you are, that the truth of you is not acceptable so if you want to be safe – be normal, please. Being thought of as funny-looking, a weak man or a manly, ugly woman, the titanic social pressure to look your gender, physical discomfort, even pain, are a small price to pay. A baggy jumper in summer heat, chest binders, hormone blockers, side-effects, surgery; being more likely to attempt suicide, be homeless, be the victim of violent crime, murder, sexual assault. Certain countries wholly out of bounds, a crime to be you, violence inevitable, media debates that aren’t kind, that make your mother flinch and rush to switch the radio off, change the subject, protect you. Having to be tolerant of intolerance, taking deep breaths and bracing yourself, standing tall – they don’t know how fast your heart is beating, how much your palms are sweating.

If you could avoid all that and happily pretend you’re a girl when you know you’re a boy – why wouldn’t you? “Mum, if I could, I probably would, but I can’t because it isn’t who I am.” And there’s the rub – it’s not a choice, it’s a truth. And it can be wonderful.

School arranged PE with the other boys, “he” not “she” – and the boys’ uniform, he left the house wearing that and the broadest of smiles. He changed his name – just one letter, but a clear mark of boyhood, a farewell to girlhood. He joined the LGBTQ+ group at school – as did every single one of his magnificent friends. I called his friends’ parents and explained we were proud of him, this wasn’t a dark secret to be discussed in hushed tones. Beautiful reactions from one and all. We are lucky, I know. One offered a friend whose son was transgender and did I want to be put in touch, others asked what they could read to learn more; another, unprompted, gave our school WhatsApp group a gender-neutral title, and a mum of a trans child told me about Gendered Intelligence, a life-saving organisation with a trans youth club. I’ve never seen a child look so delighted as my son on his first visit.

There will of course be struggles aplenty ahead – even the strong, proud trans role models my son has face a daily struggle. Just being themselves is an act of political controversy. And my son worries for his trans peers. He told me about a friend whose parents don’t accept his gender, that it would be such a relief for him to have a kind place to go, that didn’t cost money, where everyone was nice to him even if he’s wearing boys’ clothes.

Then I heard about efforts to create such a place – the LGBTQ+ community centre volunteers are crowdfunding and working hard to set up an open, accessible space for LGBTQ+ people in London. What a door opened for us when we found them. They don’t even have a building, but the community they’ve created already has been transformative: advice about our legal rights, solidarity at moments of struggle, hugs, picnics, real understanding from people who’ve been riding this wave for years. My son spent bank holiday Monday in a park, chatting to an open and generous person who was able to answer all his questions from personal experience. We’re part of a community now – it’s uplifting and gives me hope for a more compassionate future, one where we aren’t the subject of a vitriolic debate.

• Molly Mulready is a lawyer and mother of three