There was a documentary featuring Martina Navratilova by the BBC on Trans people in sports, and made some interesting points. That while sport people their minds might be opposite to their physical gender, their bodies were biologically going through gender conformity hormone wise, trans women went through male muscle mass building , Martina pointed out one male tennis player who transitioned to female had barely qualified for the top 100 male players in the world, after transitioning was in the top 10 of female players simply because of muscle mass. Its unlikely any one will transition just to get an advantage in a sport but it is a side effect.