Semenya’s win is not without controversy as last summer, the Court of Arbitration for Sport suspended the "female hyperandrogenism" policy, which was adopted in 2011 by the International Association of Athletics Federations (track and field's governing body) and deemed high levels of natural testosterone as a competitive advantage. Semenya is believed to be one of the athletes who benefits from the genetic condition yet she has never confirmed her condition.
This underscores the problem of the gender-is-nothing-but-a-construct argument, also known as social contructivism. Biology determines success at the Olympic level, and does so in a discriminatory way. In the case of Semenya, he has testosterone levels of a male. This is typical of those with a Y chromosome like Semenya has. Testosterone levels heavily influence such fundamentals of physicality as muscle mass and muscle density. Having the testosterone levels of a male means he is competing with the physique of a biological male regardless of other non-conformities that may be at play here. He should either competed with male competitors. The only way to justify him competing with females is to argue for the elimination of gender classification in athletics. Keep in mind that this would all nut eliminate female athletics, as the best females generally cannot compete with the best males.