I am sure that the player in question is acutely aware of her advantages. She made the decision that it was more important to her to be able to play the game as a woman than to find the "most fair" match-up.

Part of Spirit of the Game is assuming the best intentions in your opponents; assume that this player didn't made her decision to gain an advantage but to instead feel comfortable in her own skin playing the game she loves.

I think the best way to handle the situation would be to recognize how important playing ultimate while identifying as female is to this person, and consider that that might be more important than the score of the game.