I'm looking for a fanfiction in which Dean was born female, but thinks he's male. I remember that when Sam was up to about 4 years of age he thought that he was an extension of Dean. I also think that Dean went to hell and when he came back he turned to his male version. I think Castiel was in the story. Don't know if there were pairings in the story.

Thanks for the help of finding the story.