The Mushroom Retainers were presumably female, since some sources call them "Mushroom Girls." I always thought Birdo was a species (or 3, green, purple, and red; or maybe it's 3 sup-species or 3 races, I don't know the "Mario" taxonomy) not an individual. The Birdo character is named Catherine. Cheep-Cheeps are male and female, they're fish! Lakitu is a woman, right?