This is something I increasingly muse on, as I see dozens of posts from women here who say "I could so easily have been trans" as they describe a tomboy-ish childhood.
I never really thought of myself as a tomboy. I was lucky enough to be a child in the 70s when it was - or seemed, perhaps with rose-tinted spectacles of nostalgia - perfectly normal to wear trousers and play with my toy garage one day, then a dress and play with Tiny Tears or Sindy the next. The most unease I remember having about my body at that time was that it didn't develop quickly enough compared to my friends; I was a skinny ironing board of a child well up to 14/15. I didn't have lots of friends but those I did have tended to be female rather than male. Physically I was quite risk-averse and not up for the more rough-and-tumble male-driven games. As a horse-mad child I went through phases of playing as a horse (and also a rabbit, after I read Watership Down 😄), but never actually believed I was one.
This isn't to say my childhood was idyllic and problem-free: my dad was an abusive alcoholic with a hair-trigger temper, I was bullied all the way through school, we didn't have much money. But I did grow up with the belief that I could do any job I wanted, that I should earn my own money and be independent. I knew from a very early age that I didn't want children, didn't want to play a maternal role. Then in my late teens, around Sixth Form age, I discovered feminism and never left it. I read The Women's Room, devoured Virago books, discovered Angela Carter and Margaret Atwood and Germaine Greer...I was, have always been and still am happy to declare myself a feminist, even when the word has attracted negative connotations in some people's eyes.
I've never wanted to be a boy or a man, even when exposed to sexism, sexual assault (thankfully comparatively minor) or any other sex-based discrimination. I don't think I would have been ripe to be trans as a child or teen. But I'm not 'cis'. I don't have a gender identity. I'm just me. I have always been me, and that me has always been female, regardless of any insecurities about my body I've had at various times of my life.
Can anyone else here relate?