There are Male, Female and Genderless (Legends) Pokémon, but why there are no Hermaphrodites/Androgynes?
Slugs like [redacted], it should end that Male/Female debate are Hermaphrodites for example.

Gender symbol could be that of Mercury, as it's used by IRL Herms whose genitals were chopped off and Hermes the Greek god was one.
Of course, unlike for slugs, for humans only one of the genitals is working.