Caster Semenya is the top favourite for the 800m gold in Rio but her fast times this year have stirred up a gender debate again - in connection with a CAS ruling that outlaws a testosterone cap on intersex athletes.Rio de Janeiro (dpa) - The women‘s Olympic 800 metres heats start on Wednesday amid growing fears that a reignited gender debate will explode once Saturday‘s final has been contested - with unforeseen consequences.South Africa‘s Caster Semenya is the big favourite and it is not being ruled out that she can attack the mark of 1 minute 53.