If Semenya had been categorized according to his sex, he wouldn't be considered amongst the very best athletes. He is basically a middling standard 800m male runner who has been able to make a career on the back of what is essentially an administrative error.
Talent scouts specifically sought out males like Semenya who were erroneously registered as female at birth, knowing that their male physical advantage would give them an edge in women's competitions.
The specific condition he has (5-alpha reductase deficiency) is one that only affects males, conferring upon them internal testicles and a micropenis. But male development, including all the testosterone-driven advantages that distinguish male and female athletic performance, is otherwise normal.
His gold medal in the 2016 Rio Olympics women's 800m, along with silver and bronze being taken by two other males with similar conditions, is the reason why World Athletics (then the IAAF) and, later, the IOC started to move policy away from eligibility by identity documentation to empirical testing of sex advantage.
The policy change discussed in the linked article wouldn't have happened without athletes like Semenya taking advantage of the previous flawed policy, to the detriment of female athletes.
Caster Semenya is a woman, not sure why you're referring to her as him. The fact that she has a potentially unfair advantage due to her unusual genetics in women's competitions doesn't in any way make it fair to refer to her in this way.
If you look at accounts from Semenya's early life there is evidence against his account of growing up as a girl. For example, there have been school photos published showing him wearing a boy's uniform near to a group of girls who were all wearing girl's uniforms. His former school headmaster, when interviewed years later, said he thought that Semenya was a boy and was very surprised to hear that he was now competing in women's athletics.
And of course he would have gone through male puberty, not female puberty. This would have been obvious then, and the result of this is obvious now if you see him in interviews. Male-typical build, male-typical vocal tone. Even his now-wife assumed (correctly) that he is male when she first met him.
Semenya has to double down on this narrative that he is a woman otherwise he will have to admit that his successful sporting career as a woman will have been a lie.
Even if you believe that it is the case that she lived her early life as a male, at the point that a person has made it clear that they have some preferred pronoun/is trans would it not just be disrespectful to intentionally refer to them counter to that?
Talent scouts specifically sought out males like Semenya who were erroneously registered as female at birth, knowing that their male physical advantage would give them an edge in women's competitions.
The specific condition he has (5-alpha reductase deficiency) is one that only affects males, conferring upon them internal testicles and a micropenis. But male development, including all the testosterone-driven advantages that distinguish male and female athletic performance, is otherwise normal.
His gold medal in the 2016 Rio Olympics women's 800m, along with silver and bronze being taken by two other males with similar conditions, is the reason why World Athletics (then the IAAF) and, later, the IOC started to move policy away from eligibility by identity documentation to empirical testing of sex advantage.
The policy change discussed in the linked article wouldn't have happened without athletes like Semenya taking advantage of the previous flawed policy, to the detriment of female athletes.