Cisgender person - person whose brain's sex matches their genitalia at birth.
Transgender person - person whose brain's sex DOESN'T match their genitalia at birth. Causing what's knows as "Gender Dysphoria"

For more info see w.wiki/DScd (trans topics) and w.wiki/DScf (Causes) (Wikipedia)

You can change your physical attributes, hormones, genitalia etc., but you can't change your brains.

IMO: If you have female brains from birth, it doesn't matter what genitalia you were born with, you will always be a woman.

Nonbinaries are valid BTW

Female brain + female genitalia = Woman
Female brain + male genitalia = Trans Woman
Male brain + female genitalia = Trans Man
Male brain + male genitalia = Man

This is a simplified example.

Relatable

Vibe