Gender.

Boy-Girl
Beau-Belle
Husband - Wife
King - Queen
Bachelor - maid
Boar- sow
Bridegroom-bride
Brother-sister
Ox
duck
Cock
Colt
Drake
Dog
Drone
Fox
Hero
Tailor
Author
Giant
Heir
Lion
Actor
Poter
Doctor
Hunter
Emperor
Master
Brother -in-law
Father-in-law
God-father
Gentleman
Billy-goat
Bull-calf
Cock-sparrow
He-goat
He