I was bullied, picked on, beat up for most of my childhood because other kids thought I was effeminate and gay.
My Sister-In-Law told my wife when she first met me 15 years ago that I seemed pretty feminine.
When I Moved to the US, people would ask my wife if I was gay. My Mum told me I have been dressing as a girl since I was 11 yrs old and when I was 5, a guess I threw a huge tantrum because she wouldn't let me wear a dress. And a girl I knew in High School, once she found me on FB, said that my being a girl now made sense. Then there was the many other times I've been seen as female over the yrs before transition.
My favorite one though was when my mother-in-law pointed to me in a group photo of me with my college buddies and asking my wife, "So who is this girl?"
Given how short I am, my small hands and feet, no Adams apple and my androgynous voice in pretty sure my own body was trying to tell me I was a girl.
One time at a former employer, I told a friend I was transgender. I hadn't started transition yet and she replied with, "so you used to be a girl, right?" O.o
And I get called ma'am on the phone every time. I haven't changed my voice or anything.