It started when you were not yet two. You were fascinated by the way that children’s shops were so utterly divided: “boys’ stuff” and “girls’ stuff”. You liked to tell me which was which. But, trying to bring you up to reject the idea that clothes and objects were connected to your genitalia, I always said, “No, these are for everyone.”

You looked at me with your huge eyes. It’s hard for a small child to disagree with all-powerful adults. But I felt uneasy.

You were right and I was lying. You understood the message of the marketing and my pretending couldn’t make it go away.

You soon started to say that because you liked the boys’ things you must be a boy. You wanted to cut off your hair, refused to wear dresses and made puking faces if someone offered you something pink. I didn’t mind. I let you: my sisters and I had done similar things as children when we went through a phase of really liking George from the Famous Five.

I don’t disagree with you openly when you say you’re a boy, either. I know you’re too young to really understand the complex reasons why girls and boys are supposed to act, dress and feel differently in our society. You’re not feminine. That’s what you mean.

What if you become that dangerous thing - a teenager who feels she doesn't fit in her own body?

But then. Over the last few years I’ve started reading about gender, and getting scared for your future. You see, it’s now controversial for me to say that, contrary to your opinion, I know you’re not a boy.

There are a lot of voices out there on the internet who want to disagree. They will tell you the opposite. And they are becoming more mainstream every day, convincing young people who are vulnerable that they can do the biologically impossible: change sex.

What if you become that dangerous thing: a teenager who feels she doesn’t fit in her own body? As a teacher, I see this with teenagers every day, manifesting in anorexia and self-harm; we recognise that this view of the body is pathological, although apparently as far as their “gender identity” is concerned the opinion of teenagers is all-powerful.

So what if you become convinced that your particular body is “wrong”? Soon, from the vulnerable age of 16, you will be able to start down a road with serious drugs that will alter you for ever, drugs that will make you infertile, surgery that will cause side-effects for the rest of your life. And various “liberal” parts of society will call me an abusive parent for disagreeing with all of this.

I look at you: your perfect body. I can’t bear the idea that someone may try to convince you that you’re in the wrong one because you like dinosaurs and pirates, and hitting things with sticks.

I hug you and whisper to you as I have done since you were born five years ago: “You are my perfect girl.”

My girl. Nothing can change that.

Anonymous