Moreover, "Gefn" is one of the alternate names of Freya, the Norse goddess of procreation. It is entirely conceivable that Gefyon is merely an aspect of Freya in the same way that Morrigan in Celtic mythology has a multiplicity of aspects. To compound this line of argument, Gefyon, like Freya, was a prophetess gifted with a view into the future but unable to alter it; Gefyon also possessed a magical necklace, much like Freya's Brisingamen.
Alternate spellings:
Gefjon Gebjon