Who are the parents of Medusa?

According to some sources, her parents were the primordial sea gods Phorcys and Ceto, and they were the parents of her, her sisters the Gorgons, and Echidna. But according to other sources, Medusa was a beautiful human woman who served as a virgin priestess to Athena. But then she was raped by the Sea God Poseidon, and to add insult to injury it happened in the temple itself. And because Athena couldn't punish Poseidon, she punished Medusa for the insult, transforming her into the terrible monster.