Exactly, the idea that a person is transgender is a laughable fantasy. Only God alone decides gender.
Gender used to be a language term. Only place I’ve ever seen it, prior to last decade, was in junior high French class. Dr John Money popularized using gender for sex after his first sex change surgery, a total failure, as child did not accept his sex change. Money maintained it succeeded, and thereby we use gender in place of sex. I’m guessing Money used gender instead of sex as some part of his brain knew sex changes were impossible.