USA Powerlifting banned a transgender woman from competing in May, through policy that is at odds with global health standards and International Olympic Committee (IOC) guidelines.

Why it matters: Outside of sports, U.S. federal policies prevent transgender people from serving in the military and aim to prevent access to homeless shelters or health care if they do not present as their birth gender, regardless of their physical transition status.

Reality check: Decreased muscle mass, decreased strength and body-fat redistribution are three standard effects for transgender women receiving estrogen through hormone replacement therapy (HRT), as shown by the World Professional Association for Transgender Health (WPATH) and UC San Francisco's Center of Excellence for Transgender Health.

WPATH sets global medical standards for transgender health services.

sets global medical standards for transgender health services. These physical changes are expected to occur between 3-6 months after beginning HRT, according to the Whitman-Walker health clinic in Washington, D.C. Whitman-Walker says it has provided care to the LGBTQ community since 1973 and formal medical services for transgender people since around 2005.

to occur between 3-6 months after beginning HRT, according to the Whitman-Walker health clinic in Washington, D.C. Whitman-Walker says it has provided care to the LGBTQ community since 1973 and formal medical services for transgender people since around 2005. These medically backed findings contradict USA Powerlifting's claims that transgender women have "significant advantages" over other women in competitions.

What's happening: USA Powerlifting created its policy on transgender athletes in January, after powerlifter JayCee Cooper's application to compete in Minnesota was denied based on her status as a transgender woman.

The policy bans the use of HRT for competing transgender men — as well as for "any and all medical conditions" — and bans transgender women with or without the use of HRT.

for competing transgender men — as well as for "any and all medical conditions" — and bans transgender women with or without the use of HRT. The nonprofit "Gender Justice" has lodged a discrimination complaint on Cooper's behalf against USA Powerlifting with the Minnesota Department of Human Rights, Outsports reported — but USA Powerlifting refuted the claim.

"Gender Justice" has lodged a discrimination complaint on Cooper's behalf against USA Powerlifting with the Minnesota Department of Human Rights, Outsports reported — but USA Powerlifting refuted the claim. The USA Powerlifting board of governors discussed the issue this month before the Open Nationals, eventually voting against a policy that would have allowed transgender women to compete.

The big picture: The IOC's guidelines on transgender athletes say a transgender woman is eligible to compete in female competitions after proving her total testosterone level has been below 10 nanomole/Liter for at least 12 months.

The bottom line: Beyond the effects of HRT, "there is no direct or consistent research suggesting transgender female individuals (or male individuals) have an athletic advantage at any stage of their transition," according to a U.K.-based 2016 study — which analyzed 8 peer-reviewed research articles and 31 sport policies.

There is no "evidence that going through a male-typical puberty will necessarily give transwomen or transfeminine individuals an advantage" over other women, Yale bioethicist Katrina Karkazis told Vice News.

Go deeper: See a list of the policies on transgender athletes held by sporting organizations around the world.

Editor's note: This piece has been updated to include USA Powerlifting's response and to correct that Whitman-Walker began formal medical services for the transgender community in 2005 (not 1973).