Gender is a construct and performative. Sex is a genetic state with more than two possibilities, and the Olympic committee cares about sex not gender. People like Trump and Rowling don’t understand or acknowledge the difference between sex and gender, so I suppose it’s accurate to say that they are questioning either. Still, I think in writing about it we should say they are questioning her sex as that is what would disqualify her from women’s boxing?
Edit to add: sex is also a legal status and the Olympic committee cares about that and surgical status and some other stuff.
Also, personally I think trans women are women. And it’s wrong for anyone to question this athlete’s trans status as well.