I wasn't talking grammatical gender, I was talking "sex". The "sex" of a "rex" is male. The "sex" of a "regina" is female.
"uterus" or "uterum" can be masculine or neuter in gender. "manus" (hand) may look masculine but has feminine gender and adjectives must agree (e.g. dextera -- right). But neither uteruses or hands are male or female.
Grammatical gender is a source of confusion, and has been exploited effectively by the social-reengineers on the left.