Bill/River
You go far enough into the future, you see every kind of cross-species reproduction imaginable. It's rather comforting to know that humanity, for all it's long history of vile prejudices and nonsense over the mixing of the "races," eventually humps its way across the universe. It's a beautiful thing.
Yes, champion complainer that one. Though a dear friend. I'm glad to know he and his makeshift body are still around.