Wait, so Odin's great-grandmother was a cow? You learn something new every day!
That tipped me in favor of the Norse.
I think that technically, Odin's grandparents came from the Cow's saliva when she spit onto the ice and salt.
Let's just say that if Greek myths are defined mostly by tragedies, the Norse myths are defined mostly by comedies. Thor also had to go cross-dressing to trick a giant into marrying him. And Loki transformed himself into a female horse, and got pregnant, to help out the gods on some task. The Norse myths were basically their equivalent of Family Guy (with Loki = Stewie).
Ragnarok: