Marcin Urbas has demanded Namibian sprinter Christine Mboma goes through a sex-affirming test.
The former Polish athlete says he simply does not believe someone who can run the 18-year-old's times is "definitely is a woman."
As a teenager and with an Olympic silver medal in the bank, Mboma has a bright future in track and field, provided she is allowed to keep competing.
The Namibian athlete surged through a star-studded women's 200m field to claim silver in 21.81 seconds, a new under-20 world record, per Insider.
Her impressive speeds have led Urbas to question why she is better than him at that age, with the ex-athlete demanding she undergoes a gender test.
"I would like to request a thorough test on Mboma to find out if she definitely is a woman," said Urbas, per Marca.com.
Due to her naturally high testosterone levels, Mboma is barred from competing in races between 400-meters and 1000-meters, as per the Olympic rules.
"The testosterone advantage of Mboma over other participants is seen with the naked eye. In construction, movement, technique, at the same time as speed and endurance. She has the parameters of an 18-year-old boy. At that age, my PB was 22.01, and she has done it in 21.97 in Tokyo," Urbas added.
Urbas, who is now a sprinting coach, is the Polish record holder for the 200-meters with 19.98 seconds.
Fellow Namibian, 18-year-old Beatrice Masilingi, who finished sixth, also impressed by reaching the 200m final in her first major championships.
But the presence of both women in Tuesday's race has reopened debate about track and field's complex rules regarding women born with elevated testosterone.
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.
What's more, their impressive performance has seen World Athletics president Sebastian Coe wonder if the DSD guidelines need to be reassessed, per Independent.
Mboma and Masilingi were training for the 400m before being told they would be unable to participate last month, prompting them to enter the 200m.
But the manner of Mboma’s late dash gives Coe the feeling that the advantages of their testosterone levels were almost as clear in the sprints.
"It was pretty observable that the last 30 or 40 meters were impactful," said Coe on Wednesday, August 4.
"But, actually, I think that vindicated the decision about 400. If you are finishing a 200m like that, you extend the runway… That in a way supports the judgment that was made."