A Kiwi transgender athlete is speaking out against world swimming's governing body effectively banning transgender women from competing in women's events.

Mountain biker Kate Weatherly told Breakfast it's "pretty horrifying" some people think trans women will ruin women's sport.

Her comments come after FINA widely adopted a new "gender inclusion policy" on Monday which only permits swimmers who transitioned before the age of 12 to compete in women's events.

"This is not saying that people are encouraged to transition by the age of 12. It's what the scientists are saying, that if you transition after the start of puberty, you have an advantage, which is unfair," a spokesperson for FINA's president said.

Weatherly said there are "way bigger issues" in women's sport than transgender athletes, such as economic disadvantages and women being able to achieve "rights in general".

"The idea that a few trans women coming into a sport - and often times not even winning - and that's what's going to ruin women's sports is pretty horrifying."

Weatherly said "we are all women", calling on other sports to stop trying to separate transgender and cisgender women.

She remarked trans women having to compete in a separate, different category - FINA are proposing an "open competition category" - serves to continue to "other" trans people.

Weatherly also said such a category would limit competitiveness due to small numbers of transgender athletes.

The mountain biker said FINA's policy is a "very cut and dry line" and that its new rules are masquerading as inclusive. Weatherly said the policy essentially bans trans women from being able to compete.

Weatherly said some people ignore the disadvantages of a transition, which mean transgender athletes have longer recovery time, a lower red blood cell count and have more difficulty building and maintaining muscle.

The testosterone levels of trans women athletes is also often reduced "very low" below that of cisgender women, Weatherly said.

A 'very dangerous' precedent 

A New Zealand professor who works in the field of the sociology of sport told Breakfast she finds FINA's policy "deeply disappointing and very troubling".

"FINA refers to this as a gender inclusive policy but in fact it's an exclusionary and discriminatory policy. It sets a very dangerous precedent for other sports to follow, creating exclusionary environments," Holly Thorpe said.

Like Weatherly, Thorpe said it is "absolutely not true" transgender women put women's sport at risk.

"I've spent almost two decades of my life researching and advocating for women in sport and some people say this puts women's sport at risk. That is absolutely not true. Transgender athletes do not pose a risk to women's sport," she said.

"I really hope in Aotearoa New Zealand our sports organisations are really coming at this from a place of inclusion, because this is a dangerous moment.

"I think other sports organisations are jumping on this bandwagon, which I think is very problematic, and we need to make sure these are transparent processes, they're accountable, and that they take human rights into perspective here."

Other sports have also been examining their rules around transgender athletes.

Cycling's governing body recently updated its eligibility rules for transgender athletes with stricter limits that will force riders to wait longer before they can compete.

The International Cycling Union (UCI) increased the transition period on low testosterone to two years, and lowered the maximum accepted level of testosterone. The previous transition period was 12 months but the UCI said recent scientific studies show that "the awaited adaptations in muscle mass and muscle strength/power" among athletes who have made a transition from male to female takes at least two years.

Top image: Mountain biker Kate Weatherly (Source: Breakfast)

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