Olympic silver medallist Christine Mboma and her Namibian teammate Beatrice Masilingi, who are both unable to compete at certain events due to differences in sexual development (DSD), qualified comfortably for the 200m final at the World Athletics Under-20s Championships on Friday while Sasha Zhoya broke the age group 110m hurdles world record.
Masilingi, who took silver in Thursday's 100m final behind Jamaica's Tina Clayton, was the fastest of the finalists as she won her semi-final in a championship record time of 22.19sec.
Nigeria's Favour Ofili was second quickest in 22.37sec with Mboma just behind, having also broken the championship record in the first semi-final in 22.41sec.
Both Mboma and Masilingi are determined as having differences in sexual development (DSD) -- or "intersex" athletes -- with naturally high testosterone levels.
Under World Athletics rules, the two sprinters' rare physiology is deemed to give them an unfair competitive advantage in track events ranging between 400m and one mile.
Zhoya, who was born and bred in Australia to a Zimbabwean father and French mother, produced a superb semi-final run to break the under-20 world record for the 110m hurdles and then said he had not been happy with his run.
"There was a lot of mistakes, I hit the last four hurdles," he said. "My coach will have a stern word."
As he crossed the line: "I said to myself 'Ah well!'"
But he still had the record.
"One of my goals has been achieved, I can put a cross next to it, the world record is done," he said.
The 19-year-old's time of 12.93sec was marginally quicker than the 12.99sec set by another Frenchman, Wilhem Belocian, in 2014 and equalled three years ago by Jamaican Damion Thomas.
Both finals are scheduled to take place on Saturday.