Most of you have probably heard of Kathoey - Thai "ladyboys", but did you know that Thai tradition considers them to be a separate gender?
The Samoan Fa'afafine are biological males who are raised like females or as a third gender.
The Ninauposkitzipxpe, from the Blackfoot tribe from Canada, are biological females who are treated as a third gender that isn't restricted by the societal constraints placed on women.
Plus much more.