You are utterly clueless. The SRY-gene which is inside the Y-chromosome is what causes maleness. All XY persons have this gene. And they should all be considered male when it comes to sports.
In some cases the SRY-gene may transfer to an X-chromosome. That will cause an XX person to have male characteristics. Only persons without the SRY-gene in the body should be allowed to compete in the female category.
Caster is an XY person. He is by all chromosome metrics a male. And he should not be allowed to compete in the female category.