When she joined a women’s team in 2004, she was told to keep quiet about her past.
“I pretty much played under the radar because I was told to,” she tells SBS News.
“I had a very, very good year, and I was like, 'wow, this is good, not a problem whatsoever'. The initial experiences are just wonderful.”
But after her first successful season, she was outed to her teammates and faced transphobic abuse as a result.
Today, she says many trans athletes face challenges when trying to participate in sport.
“The experience, I think, is still the same, where we have to rely on the goodwill of coaches and officials and people to make our mark,” she said.
She’s one of many in the rugby community concerned about new guidelines from the rugby's international governing body which restrict transgender participation.
The guidelines released by World Rugby in October called for transgender and non-binary players to be banned from competing at the elite level of the women’s game on safety grounds.
"Safety and fairness cannot presently be assured for women competing against trans women in contact rugby," the governing body said in a statement.
“I was very, very disappointed,” Ms Layt said. "The biggest thing that upset me is [the lack of] our voice. There were no transgender women rugby players in the working groups that decided this."
Ricki Coughlan, one of Australia's first out transgender sportswomen, spoke out about the ban on Twitter, while Australia’s gay rugby clubs also came together in opposition to it.
“I think this is in complete opposition to what the values of our game are,” said Don Rose, president of Australia's first gay and inclusive rugby union club The Sydney Convicts.
“There are people within our clubs and within our community who are extremely concerned about what this does for the rights of trans people to be involved in our sport.”
The testosterone debate
The participation of gender diverse athletes in elite level sport is a vexed issue and sporting bodies are still working to find the best way of ensuring a balanced playing field for all competitors, particularly in women's sports.
It is commonly accepted among sports scientists that cisgender men have physical advantages compared with cisgender women. As such, many organisations that allow transgender participation, including the International Olympic Committee, place additional eligibility requirements and restrictions on transgender women athletes to negate any perceived physical advantages they may have had before they transitioned.
Among those requirements include strict limits on certain hormones such as testosterone.
“The debate about testosterone - whether testosterone is performance-enhancing, at what level is it performance-enhancing, what sports it is performance-enhancing - is a hotly contested issue,” said Monash legal lecturer Eric Windholz.
World Rugby's recommendations take a different approach to the issue, advocating an outright ban on transgender women participating based on safety, not performance grounds.
According to the governing body’s scientific research, there was a minimum 20 to 30 per cent increase in injury risk factors during tackles involving typical male-bodied and female-bodied players, even when accounting suppressed levels of testosterone in women.
World Rugby has defended its proposal, arguing the risk of serious injury to athletes at the elite level is very real. But the body acknowledges there have been no direct studies examining trans women rugby players, drawing its findings from existing research into biological differences, hormone suppression and known risk factors.
Ms Layt says those findings fail to account for the varying shapes and sizes of real-world athletes.
“In our lived experience as women rugby players, we’re not the strongest on the pitch … and we lose testosterone as we go along” she said.
“I believe there should be a case by case basis for transgender women playing the game and a blanket ban is not necessary.”
Under the proposal, transgender men would be allowed to compete against cisgender athletes, if they signed a waiver.
“[It’s] saying trans men have the choice to accept the risk, the same risks that you're saying cis-gendered women can't accept when competing against trans women,” Mr Windholz said.
World Rugby’s guidelines only apply to the elite level of the sport, and it is up to the discretion of individual countries to apply them. They don't impact what happens at the grassroots level.
Rugby Australia has taken a different approach to the issue. It is one of several sporting codes to commit to the wider inclusion of transgender and gender diverse athletes in its competitions.
In 2018, the board introduced a dispensation process that requires gender diverse participants to seek the consent of a medical specialist and an assessment from an independent coach before they are eligible to play.
In October, it was one of eight sports federations, including peak bodies for tennis and Australian rules football, to issue guidelines aimed at encouraging the participation of transgender athletes.
Rugby Australia states in its community guidelines that it "is committed to supporting a player’s participation in the gender with which they identify".
"We want, need and affirm trans and gender diverse people in rugby, not just because everyone should be able to play and inclusion is the right thing to do, but because rugby benefits from trans players, spectators and communities."
"Trans people live, work and play across Australia, and it is important that rugby reflects this anywhere sport is played."
Mr Rose said Rugby Australia had a strong track record of consulting with the community over LGBTQI+ policies.
“I think, importantly for us here in Australia, with such a competitive market for sports and football clubs, what we should be doing is trying to give everyone who wants to play [a chance],” he said.
But he warned other less tolerant countries may be less likely to follow Australia’s lead in embracing inclusion.
“The concern for me is that other nations, that might not be as far on the journey as we are here in Australia, will just follow the lead of World Rugby.”
LGBTQI+ Australians seeking support with mental health can contact QLife on 1800 184 527 or visit qlife.org.au. ReachOut.com also has a list of support services.