An Australian federal court is hearing an appeal in a case that could have national implications for biological women and female-only spaces.

The lawsuit began after a biological man, who identifies as a woman and goes by the name “Roxanne Tickle,” attempted to join a social networking app, Giggle for Girls, which is exclusively for women. Alliance Defending Freedom (ADF) International, the legal nonprofit supporting Giggle CEO Sall Grover’s defense, stated in a news release that the Full Court of the Federal Court of Australia last summer decided in favor of Tickle. According to its ruling, Giggle’s removal of Tickle from the women-only platform constituted indirect discrimination.

Tickle, whose birth certificate was amended to read as female, had sued the app after he was denied access to the platform, arguing that if he was “legally permitted to identify as female,” he should have access to women-only spaces. According to ADF International, Giggle for Girls said that his actual male sex disqualified him from using the app.

However, the court last summer ruled that “[S]ex is not confined to being a biological concept referring to whether a person at birth had male or female physical traits, nor confined to being a binary concept, limited to the male or female sex.”

The appeal hearings began Aug. 4 and are set to conclude Aug. 7.

In the release, Grover said she is optimistic about the case.

“I know we are right & I know that reality always wins — eventually,” she stated. “Reality is inescapable. The law has to reflect reality. In reality, no man is a woman so therefore no man should legally be a woman.”

Robert Clarke, director of advocacy for ADF International, called the court’s previous ruling a “flawed judgment that undermines protections for women.”

“Sex is not a feeling — it is a biological fact, and it cannot be changed,” he stated in the release. “This appeal is a defining moment: the Court must choose between ideology and reality.”