seiðr is magic. this place has magic and it can make people be older or younger than they should be, or it can make a man be a woman or a woman be a man, or it could make you and i switch bodies. it has never done these things to me, but my sister's husband is a seið-man and it changes him at times.
it sounds like a tale to be told round the fire, i know, but we live in the stars with the gods now and it is what we must expect.