“It did not register, as we get men trying to enter all the time. Mr Tickle passed our AI facial recognition test, which was deliberately set at 94 percent accuracy, meaning that some men will get through,” Grover, who refuses to refer to transgender women as women, told Al Jazeera.

“The rest we remove manually.”

“When he contacted me by phone and I heard a man’s voice, I hung up, but again, this was not unusual,” Grover added.

Grover’s decision to restrict her app to “cisgender” women – women whose birth sex aligns with their gender identity – has not only put her at the centre of the culture war over gender, but in the legal crosshairs as well.

As someone who identifies as a woman, Tickle argues that she is legally entitled to use services meant for women and has been discriminated against on the basis of gender identity.

In a case being watched around the globe, Tickle is suing Grover under Australia’s Anti-Discrimination Act, relying on a 2013 amendment that added gender identity to the list of protected categories.

At stake are contested definitions of sex and gender and, ultimately, the very question of what it means to be a woman.

For trans activists, a ruling in favour of Tickle, who is seeking 200,000 Australian dollars ($128,320) in compensation, would be a vindication of their long struggle to be treated just like other women.

For so-called gender-critical feminists, a win for Grover would affirm the need for female-only spaces that take into account the essential differences between men and women.

After hearing several days of arguments by the two sides at the Federal Court of Australia in Sydney earlier this month, a judge is expected to hand down his decision in Tickle v Giggle in three to six months.

Grover created Giggle in 2020 upon returning to Australia after a stint working as a screenwriter in Hollywood, where she says persistent social media abuse by men landed her in therapy.

“I wanted to create a safe, women-only space in the palm of your hand,” Grover who spent 500,000 Australian dollars ($320,800) on building the site, said.

As far as Grover is concerned, “women-only” spaces should not include trans women like Tickle.

Tickle, who has undergone vaginal and labial surgery and changed her sex to female on her birth certificate, joined the app in 2021 after her application was accepted by gender recognition software designed to screen out men.

Tickle’s account was restricted about six months later after manual screening.

“The evidence will show that Ms Tickle is a woman,” Tickle’s barrister Georgina Costello told the court, according to local media reports.

“She perceives herself as a woman. She presents herself as a woman.”

Costello also told the court that Grover had mounted a “global campaign” against Tickle, including persistently misgendering her in public statements and selling offensive merchandise featuring her image.

“We say because of the way Grover views transgender women, she was unable to see that a transgender woman is a woman,” Costello said.

Tickle’s lawyers did not respond to a request for comment.

Hilary Kincaid, principal solicitor at Sydney firm Kincaid Legal, said the case is complicated for multiple reasons apart from its contentious subject matter.

“It would be far more clear cut if there were physical premises,” Kincaid told Al Jazeera.

Kincaid said Australia’s arcane laws and regulations for community and sporting clubs will be among the relevant considerations in the case.

“Speaking very generally, you can exclude someone from private premises, depending on the terms of the admission,” she said.

“So if there’s a sign up in a club, saying you have the right to refuse admission at the club’s discretion, that can be allowed.”

The case has drawn significant international attention, particularly through social media, not least because of Grover’s openness to giving media interviews and her efforts to raise funds for her legal defence.

Grover said she has raised about 546,000 Australian dollars ($350,314) so far but initially struggled when she was kicked off a number of fundraising platforms.

“Luckily we had the skills, so we were able to build our own platform,” she said.

The Australian legal stoush is seen as a test case by gender-critical feminists, also known as Trans Exclusionary Radical Feminists (TERF), both at home and in other countries such as the United States, Canada and the United Kingdom.

They argue that businesses and organisations should be able to exclude transgender women for reasons including safety and fairness.

“Gender identity is overriding sex and nobody’s explained why,” Angela Jones, a women’s rights activist and supporter of Grover who co-hosts the TERF Talk Down Under podcast, told Al Jazeera.

“Women’s rights have been taken away, and this has impacted women who are in the lowest socioeconomic background or victims of domestic violence or whatever. We always thought ‘that the rules are reasonable’ and our rights would be granted but in the last three or four years we have found we have no rights at all. We have no single-sex spaces”.

ACON and Transgender Victoria, two of Australia’s leading trans activist groups, declined to comment on the case.

Grover accused trans activists of doing “everything they can” to shut her business down.

“They have taken away not just a valuable service for women, but my livelihood,” she said.

“But if I was just in it for business, I would let others in, it’s important to me that the space is female only. I am in fact the one here who is suffering financial loss.”

While many corporations have expressed their support for trans rights amid growing public acceptance of LGBTQ people in recent years, businesses have also faced blowback for associating themselves with the issue.

Last year, Bud Light suffered a plunge in sales after a conservative backlash to a brief partnership with trans activist and TikTok influencer Dylan Mulvaney.

In the US, Republican-led states have introduced dozens of laws to curtail trans rights, many of them aimed at restricting trans women’s participation in women’s sports and gender-affirming care for minors.

In Australia, the debate has also been polarised, as evidenced by the background of Grover’s lawyer, Katherine Deves, a former parliamentary candidate for the main conservative party.

But while conservative-run businesses pushed back against having to serve LGBTQ people in years gone by – such as, for example, refusing to cater to same-sex weddings on religious grounds – the fight over trans rights has followed a less predictable ideological script.

Many of the critics of trans activism are not religious, or even necessarily conservative, with radical feminists among those leading the charge.

Kincaid, the lawyer, said Tickle v Giggle has parallels with a recent case involving a man who took legal action after being denied entry to an art installation where women are pampered by male butlers and served champagne.

The Tasmanian Civil and Administrative Tribunal ruled that the Museum of Old and New Art (MONA) had discriminated against patron Jason Lau and that men should be allowed to view the installation.

“If MONA had created the Ladies Lounge as a club, the result may have been different,” Kincaid said.

Still, even if the court finds in Tickle’s favour, the level of compensation she might receive is unclear.

“If you are successful under the Act, you are compensated for loss, yet it would be difficult to make an argument that she [Tickle] suffered a specific financial loss,” Kincaid said.

Whatever the outcome of the case, it is all but certain to inflame the acrimonious debate over trans inclusion versus sex-based rights.

Grover said she is ready for any outcome and prepared to fight the case all the way to the High Court of Australia if necessary.

“But if we lose eventually, I will have to reincorporate the business somewhere else,” she said.