Today’s most pressing women’s rights issue is not abortion. It’s not equal pay, domestic violence, or child care. It’s whether society is willing to recognize “women” at all. Without this basic understanding, there can be no “women’s” interest demanding or deserving of protection.

That’s why Independent Women’s Law Center is representing six Kappa Kappa Gamma sisters at the University of Wyoming in the 10th Circuit Court of Appeals. The lawsuit alleges that Kappa’s national leadership ran roughshod over the sorority’s bylaws to provide membership to a biological male: a 260-pound, 21-year-old individual with a 1.9 GPA (well below the sorority’s 2.7 cutoff) who discussed his “desire to be near cadavers and to touch dead bodies” during the recruitment process. The sisters say they were forced to vote publicly and informed that a “no” vote would be a sign of bigotry and a basis for expulsion. Since joining, the male member has taken unwanted pictures of the women, asked them to describe their vaginas, and watched the girls undress.

Time and again we see injustices like what happened to these sorority sisters egged on by elitists who congratulate themselves for such devout commitment to diversity and inclusion, having already reaped the benefits of single-sex living years ago. But despite their professed commitment to inclusion, by pretending that “women” includes biological males, they in fact deprive women the say they are owed. That sounds pretty exclusionary to me.

Sadly, the district court ruled in favor of Kappa leadership. In the process, it stripped the organization’s bylaws of any meaning. “Woman,” the court said, is “undefined,” and cannot be constrained by the “circumscribed definition Plaintiffs urge.” “Woman” might mean anyone who claims to be a woman, at least according to a federal court.

Of course, this is nonsensical from a basic definitional perspective. Identifying oneself as a “woman” still requires an underlying definition of “woman.” Self-identification can never provide a definition since it has no boundaries on its own. Even an inanimate object like my iPhone can “identify” as a woman, but it’s still an iPhone.

Dissolving “woman” into an unknowable void is more than senseless, it’s extraordinarily consequential.

For one, it wrecks our ability to use language. We rely on contracts for countless purposes. If I order a shirt but receive pants, I can point to language in the contract to fix the issue. And if the supplier won’t fix it, I can take my issue to court. Interpreting contracts—including, for example, bylaws—is a quintessential duty of judging. Where activists dismantle language and threaten social consequences for those who apply ordinary meaning, we lose more than common sense. We lose the ability to function as a society.

And if that were not important enough, there’s more: the truth.

Women exist, as biologically distinct from men. And single-sex spaces are beneficial to women. That includes domestic abuse shelters, given that, on average, more than three women are killed by their husbands or boyfriends per day. It also includes sex-specific sports. After all, thousands of high-school boys can outpace star female Olympians and biological males can severely injure women on the field, as we learn again and again. And it also includes single-sex social and scholastic organizations. As Kappa itself has argued in court, “the benefits of having participated in a single-sex environment persist even after the woman has graduated or otherwise left the environment.”

Women’s organizations are worth preserving.

The fight won’t be easy. Kappa alumnae have already been kicked out for the mere act of speaking the truth. Sorority women have experienced a smear campaign, and have been accused of inventing sexual misconduct and even instigating murder.

But these women are not deterred. Women have fought for suffrage, property rights, education, and protection from violence. We are more than willing to fight for our existence and for the truth.