Plato's Symposium, explains that three sexes of human beings once existed: "children of the sun" (man and man attached), "children of the earth" (woman and woman attached), and "children of the moon" (man and woman attached). Each were once round, two-headed, four-armed, and four-legged beings. Angry gods split these early humans in two, leaving the separated people with a lifelong yearning for their other half.
interesting!