The human race and most animal species on Earth have 2 genders -
the Male and the Female.
What if we have a third gender? What would it be called? What would
be its purpose?
I would call the third gender, the Seeder.
The Male would produce sperm, and deposit it in a 'pocket' in the
Seeder's body, which has a flap to open and close the pocket. The
Female would produce the egg, but lets imagine the female does not
have a womb, so the egg would be deposited in the Seeder through a
3-person sexual intercourse, where the Male and Female would mate
with the Seeder instead of between themselves, and the baby would
be born in the Seeder's womb instead.