You are not being dumb. Yes you can, but the thing is, Semenya has XY chromosomes. Semenya has no womb, no ovaries, and male chromosomes. Basically Semeny is a man with medical problems (internal testicles), but Semenya’s father perhaps wasn’t keen on the idea of a son with no balls and so raised Semenya as a daughter - incidentally giving Semenya a lucrative prestigious career in female sports instead of whatever fate awaits an African man with no balls.
So now Semenya can either lobby for the concept of ‘woman’ to be rewritten around the world to include Semenya, or instead accept that Semenya’s parenting was not good and that Semenya’s entire life was a lie and Semenya’s sporting achievements should belong to all those unknown women who came second to Semenya in races.
Bit of a psychological dilemma, that. Hope Semenya has access to a good therapist.