Athletics' governing body, the IAAF, has said "biology has to trump gender identity" after welcoming the decision to permit restrictions in testosterone levels of female runners.
Double Olympic champion Caster Semenya twice appealed against the new IAAF rule that prevents her from running in the 800m without medication.
The IAAF said competitors now have "parity and clarity" before the championships in Doha, which begin on 28 September.
The ruling, which took effect on 8 May 2019, means those with differences of sexual development (DSD) must either take testosterone-reducing medication in order to compete in track events from 400m to the mile or change to another distance.
"I am very disappointed to be kept from defending my hard-earned title," Semenya, 28, said.
"But this will not deter me from continuing my fight for the human rights of all of the female athletes concerned."