don't know what kind of garbage they taught you in schools, but what decides the human gender is their body private parts:
a female has (vagina, breast that look like a balloon when she becomes adult).
a male has (penis), most men have their moustache & beard grow when they becomes adult.
woman is a female, man is a male
Yamato is a female, Yamato is a woman, it doesn't matter if she calls herself he, she is a woman because she has the body parts of a woman, it's like when someone is white calling himself as black, or someone black calls himself as white, that doesn't change his colour.