Have a black haired vegeta I ' ll trade for the metallic yellow ! <| sep |> That ' s physical sex , yes . But your gender here meaning nonphysical component of sex , not gender roles or anything does not have to line up , and it can lead to horrible things if it doesn ' t . I ' m not talking about fun and games here , this is an actual disorder , that is very , very debilitating on mental health . Gender dysphoria is no joke . And it ' s recognized by the APA , and listed in DSM 5 . here ' s a Wikipedia article . Now , why is there a nonphysical component to sex ? I have no fucking clue . It would seem to have to be mental , and sure enough some transgender studies have found subtle differences in brain structure that look distinct from the typical for their biological sex . They don ' t exactly look like the other sex ' s either , though , which I think could be due to the hormone environment being different . But this could all be effect instead of cause , too . Biology is still a vast unexplored field right now anyway , the only things we think we understand are so simplified as to hardly ever be exactly accurate when tested .