I think he believes he already passes. That was what he meant by that “did you know the Crime Minister is a trans woman?” thing. He seriously thought there were people who didn’t realise that he, with his man face, man voice, man walk, man posture, man clothing, total lack of make-up and masculine aggression, is in fact a man. I put it down to a combination of autism and mental “slowness.”
Or he knows he's so ugly and mannish that no one can tell he's supposed to be famale.