The powerful, 26-year-old South African is runaway favourite for the 800m, where she seeks a third world title to add to Olympic gold from Rio de Janeiro last year, and is taking on the 1500m for the first time at a major international meeting.
All of this, though, will come under a cloud of controversy at the August 4-13 championships as many feel high testosterone levels give her an unfair advantage.
Anticipating a storm, Semenya this month granted a rare interview to South Africa’s SuperSport TV channel, expressing her frustration at continually having her gender questioned.
“I don’t understand when you say I have an advantage because I am a woman,” she said. “When I pee, I pee like a woman. I don’t understand when you say I’m a man or I have a deep voice. I know I’m a female so there’s no question for me.
“I have to find a way to deflect (the questioning of her gender), so instead of allowing it to all be negative, I turn it into a positive. My family’s support system is fantastic.” After Semenya won the 2009 world title as a 19-year-old, tests reportedly revealed that she was hyperandrogenous, resulting in her body producing an abnormally high amount of testosterone, which makes her more powerful than her rivals.
An International Association of Athletics Federations (IAAF) rule limiting the amount of naturally occurring functional testosterone for female athletes appeared to have narrowed Semenya's prospects but the IAAF’s Hyperandrogenism Regulations were suspended for two years in 2015 by the Court of Arbitration for Sport, allowing Semenya to make a comeback.
Her time of 1:55.27 in the Diamond League meeting in Monaco this month was the fastest in a women’s 800m for almost a decade and there will be an expectation that she could take down the longest-standing athletics world record set by Czech Jarmila Kratochvilova in 1983.
Semenya has made a late decision to add a tilt at 1500m glory to her London programme, setting up an intriguing clash with world-record holder Genzebe Dibaba from Ethiopia.
Semenya has run the distance only once this year, winning the South African student championship in April, but she is the reigning African champion from Durban last year where she set a personal best of 4:01.19.