What do we do about women athletes with testes?

Elite sport and the measures imposed to prevent 'men' from 'cheating' by posing as women in women's events cast interesting light on notions of sex and gender. Some women have testes, organs that produce testosterone, because they are trans women or they have an intersex state. Testosterone is recognised as a performance-enhancing substance in at least some circumstances, and therefore, women with testes may possess an advantage when competing in some sport against women without testes, though this has never been subjected to rigorous scientific testing.