Masculine -- Feminine
Bachelor -- maid, spinster
Boy -- girl
Brother -- sister
Buck -- doe
Bull (or ox) -- cow
Bullock -- heifer
Cock -- hen
Colt -- filly
Dog -- bitch
Drake -- duck
Drone -- bee
Earl -- countess
Father -- mother
Gander -- goose
Gentleman -- lady
Hart -- roe
Horse -- mare
Husband -- wife
King -- queen
Lord -- lady
Man -- woman
Monk (or friar) -- nun
Nephew -- niece
Papa -- mamma
Ram -- ewe
Sir -- madam
Son -- daughter
Stag -- hind
Uncle -- aunt
Wizard -- witch