Can a PhD (Or a doctorate or an MD) choose to use a gendered title instead of Dr? For example, suppose an AFAB PhD comes out as a trans man. Is he allowed to use Mister to affirm his gender? Or is he stuck in the gender neutral Doctor zone forever? Does he have to get knighted by the British monarchy in order to get a masculine title?
While misrepresenting yourself or your credentials can be fraud, the title of PhD/Doctor (outside of MD) is not regulated, at least not in the US. It’s almost like an endorsement from the university that you passed their tests.
But that’s not very regulated either, and there are countless certifying boards (Boards of Regents, typically).
Falsely claiming to have a PhD in Neuroscience from Harvard, or an honorary Doctorate of Fine Arts from Knox College, would be fraud. But just saying that you have a PhD without specifying anything more specific is not.
And it comes up regularly - an easy example is the author of Men Are From Mars, Women Are From Venus.