Retired American track and field star Carl Lewis says South African athletics authorities have "let down" Caster Semenya, 18, amid the row over her sex. The newly crowned 800m world champion has had medical tests following doubts about whether she is actually female. Athletics' world governing body (IAAF), demanded the test three weeks before the World Championships and Lewis says Semenya should have been withdrawn. "The South African federation should have dealt with it," said Lewis. The IAAF said the teenager was first asked to undergo a gender test after she posted a world leading time of one minute, 56.72 seconds at the African junior championships in July. To put it out in front of the world like that, I am very disappointed in them because I feel that it is unfair to her Carl Lewis The test was never conducted and Semenya was allowed to compete at the World Championships in Berlin. However, the South African athletics federation denied there were concerns ...