Fact check: Do trans athletes have an advantage in elite sport?

The Tokyo Games marks the first time openly transgender athletes compete as Olympians, but the eligibility has cast closer scrutiny into whether there is an unfair advantage. The experts behind the studies weigh in.

Several trans women are set to compete in the Tokyo Games, marking the first time openly trans athletes participate in the Olympics. New Zealand's Laurel Hubbard will make her Olympics debut when she makes her first attempt in the weightlifting competition.

Hubbard's participation as a trans woman in the Summer Olympics has prompted controversy — and uproar — with critics saying her eligibility is a threat to fairness in sport. Others say the inclusion of trans athletes cannot be overlooked if there are no meaningful advantages.

DW spoke to the scientists behind leading studies on trans people in sport.

What does the science tell

us about trans athletes in elite sport?

Few studies have been done on trans people's athletic performance — and, to date, there are no published studies on trans athletes participating at the elite level, say experts. But some papers have been published in the lead-up to the Olympic Games.

One study, published in 2020, looked at US military personnel who transitioned while in service and found that trans women maintain an edge after one year of feminizing hormone ther

apy, which usually includes suppressing testosterone levels and boosting estrogen.

The research was carried out by Dr. Timothy Roberts, a pediatrician and associate professor at the University of Missouri-Kansas City, and his colleagues. They found that trans women who underwent hormone therapy for one year continued to outperform non-transgender women, also known as cisgender women, though the gap largely closed after two years. But even then, trans women still ran 12% faster.

Roberts, however, suggested the difference in running times needs additional perspective. "It was a 12% advantage after two years in run times. But to be in the top 10% of female runners, you have to be 29% faster than the average woman. And to be an elite runner, you've got to be 59% faster than the average cis woman," he told DW.

Another study, carried out by sports scientist Tommy Lundberg, found that trans women who underwent feminizing hormone therapy generally maintained their strength levels after one year.

Do trans women have an advantage when competing in elite sports?

Without hormone therapy — yes. But even with hormone therapy, current research suggests trans women still maintain an edge in strength.

"Pretty much any way you slice it, trans women are going to have strength advantages even after hormone therapy. I just don't see that as anything else but factual," said Joanna Harper, a medical physicist at Britain's Loughborough University.

Strength is one of several key factors — including explosiveness, endurance and lean body mass — that determine whether an athlete has an edge.

But Harper, whose research focused on trans runners like herself, rejects the idea that trans women competing in sport would have an "unfair" advantage, noting that there are many other factors that go into shaping how an athlete performs — including hand-eye coordination and technique, which are necessary for excelling in sports like golf.

One major factor is hemoglobin levels — which is the most important physiological factor when it comes to endurance sport. Hemoglobin in the blood

Brazilian volleyball player Tiffany Abreu, who is trans, competes in the elite women’s category

All eyes will be on New Zealand's Laurel Hubbard (right)