Has US transgender swimmer Lia Thomas reignited testosterone debate in sport?

Johannesburg — American transgender swimmer Lia Thomas has reignited the testosterone in sport debate, as she attempts to compete at the USA’s NCAA swimming championships next month.

Thomas, who began transitioning in 2019, used to compete in the men’s category and reached a world ranking of 462nd. Now, Thomas is the top-ranked swimmer in the women’s category and this has sparked an outcry from her competitors.

Pending rule changes by NCAA and USA swimming may stop Thomas from competing, as it may force her to prove her testosterone levels are less than a certain mark for three years prior. It remains to be seen what Thomas’ testosterone results will show.

In a letter, published by AFP, sent to the University of Pennsylvania and the Ivy League athletic conference, 16 University of Pennsylvania swimmers, who wished to remain anonymous said: "Biologically, Lia holds an unfair advantage over competition in the women's category.

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"If she were to be eligible to compete against us, she could now break Penn, Ivy, and NCAA Women's Swimming records; feats she could never have done as a male athlete,”

"We support Lia's mental health, and we ask Penn and the Ivy League to support ours as well," the letter reads.

"Sport is competitive by definition, and Lia's wins, records, and honours should not come at our expense, the women who have worked their entire lives to earn a spot on the Penn Women's Swimming Team.”

Meanwhile, South Africa’s Caster Semenya remains barred from competition as an athlete with Differences of Sexual Development (DSD). As a DSD athlete competing in the women’s category, it means Semenya has