We are still struggling with the language used to describe "gender variant" people. Most of the models we have today are used to defend the binary. So it is either:
1. Cis woman trapped in a man's body
2. Gender is only a social construct, so if someone assigned male believes they are a woman, they are either impostors, sexual perverts, mad or all of the above.
The twin spirit model of the Navaho's accept that a person can be born a man but also have a female spirit (female attributes/personality/identity/energy or whatever it is they mean when they say spirit.