The Fool (spoilers for all RotE books, including LST)

[londonlassie]

...I'm now convinced she's really female but the Tawny Man is convincingly male and Fitz never even considers the possibility...

Personally, I think the Fool is male. Maybe because I read Liveships first, and so didn't get the connection between the Fool and Amber until I'd already read the Tawny Man and Assassin trilogies, and by then, he was firmly cemented in my mind as a guy. I find it difficult to connect the pair of them, though - when he's "Amber", I can't think of him as male. But when he's "Beloved" I can't think of him as female.

To begin with, I wondered whether all white prophets were androgynous or hermaphrodite. It even crossed my mind that they might be sequentially hermaphrodite, alternating between male and female as the need arose. The greatest evidence against this is that the Pale Woman was utterly female. Then again, the Pale Woman was a failed white prophet who had become incapable of changing colour. Maybe she had become incapable of changing sex also.

I think Maulkin may just have it. This idea is pure genius. I've never heard of sequential hermaphrodites, but I think this could easily explain The Fool.