Secret Diary of an Irish teacher: 'Mirror, mirror on the classroom wall; what is gender after all?'

A friend of mine read an article recently; it was about a group of women who, having transitioned to men, wanted to go back. It prompted me to think: when did it all start for them? How did their sex and their gender come to feel so mismatched?
As a teacher, this is something I desperately want to understand. Gender is clearly communicated once our kids reach school age; we can tell from their uniforms. Of course, we can stick a bow on a baby girl, but I’ve often peeped into a pram and not known what I’m looking at.