The new decision will prevent the South African athlete from defending her 800-meter title at the World Championships in Doha, Qatar in September. Caster Semenya's fate isn't about running. It's about human rightsAccording to a policy recently devised by the International Association of Athletics Federations (IAAF), all athletes with a difference in sex development should reduce their blood testosterone to a specific level for at least six months — and then maintain that for the rest of their athletic career — in order to compete in events from 400 meters to a mile.The 28-year-old track star, who has naturally elevated levels of testosterone, has remained “steadfast in her defiance” of rule, according to a statement released by her representative today. A Swiss court had temporarily suspended the controversial new policy in June. If the suspension had continued, Semenya would have been allowed to compete in Doha while her appeal to have the new rules reversed is ongoing. Read MoreHowever, Monday’s ruling overturned the suspension, effectively reinstating the IAAF’s policy for the time being. Caster Semenya appeals to Federal Supreme Court of Switzerland against testosterone ruling“I am very disappointed to be kept from defending my hard-earned title, but this will not deter me from continuing my fight for the human rights of all of the female athletes concerned,” Semenya said. Her lawyer said the athlete will continue to pursue the appeal.The IAAF was not immediately available to comment. It has previously argued that its policy is necessary to ensure fair competition among women.