Balls dangle, boobs dangle. That's all there is to gender.
Everything else (face and body shaping) isn't explicitly tied to one "gender" or another and holds no weight in arbitrary categorization. You can get curvy boys with girly faces, if they have man land and no boobs, their gender's still male. You can get flat barrel-shoulders women with manjaws, if they have the basic equipment, their gender's still female. This is all purely statistical.
Gender identity, on the other hand, is related to gender phonetically only, and is whatever on earth somebody wants to be; so a female appearance with breasts and male equipment may be either male or female in gender identity with the individual's preference, despite being precisely the same physically in either situation.
In short:
Sex: Crotch (male, female, or intersex; humans can't be hermaphrodites) Gender: Whole body (see above) Gender identity: Whim and preference (new gender identities are invented by the minute to thwart society)
Balls dangle, boobs dangle. That's all there is to gender. Everything else (face and body shaping)