The idea that someone might not identify with the gender that corresponds to the sex assigned to them at birth directly contradicts those categories. “Anything that challenges that idea, of the clarity of gender, is really suspect. It’s anxiety-producing, and it makes people angry,” Griffith said.

Some Christian leaders have tried to wrestle thoughtfully with this challenge to their beliefs on gender. Russell Moore, who leads the Southern Baptist Convention’s political arm, responded to Caitlin Jenner’s Vanity Fair cover with empathy, writing, “We do not see our transgendered neighbors as freaks to be despised. They feel alienated from their identities as men or women … In a fallen universe, all of us are alienated, in some way, from who we were designed to be.” To Moore, gender is part of how humans are created by God, and it is not our role to change that.

Many others share Moore’s belief, but without the same degree of empathy. Christians are used to being challenged on the truth of the Bible; after all, a core component of the faith is sharing the good news of Jesus with those who don’t yet know him. But challenges to the Bible’s description of gender attack something basic. And in some communities, these challenges are relatively new. This may be why the language of the bathroom backlash hasn’t been overtly religious. It has been the language of self-evident truth—gender difference as a fact that requires not faith, but logic, to understand.

“It’s common sense,” said Vicki Wilson, a parent who is part of a lawsuit against an Illinois school district that has let a transgender student use the girls’ locker and restrooms. “All children must be protected and respected, and having common sense, reasonable boundaries in these private, intimate spaces is protected by law,” she said.

Under an agreement with the U.S. Department of Education that took effect in January, Township High School District 211 agreed to let “Student A,” as the transgender child is called in the legal proceedings, have access to girls’ facilities. “Student A” is to use a “private changing station” behind a curtain, and any other girls in the school are also allowed to use these stations. The other girls can also request further accommodation, like changing in a single-stall facility or getting their own schedule for using the bathroom.

With this new policy, the lawsuit claims, the 14-to-17-year-old girls at William Fremd High School “experience embarrassment, humiliation, anxiety, fear, apprehension, stress, degradation, and loss of dignity because they will have to use the locker room and restroom with a biological male.” They don’t want this person to see them without their clothes on, and they don’t want to have to look. They “are afraid of having to attend to their most personal needs, especially during a time when their body is undergoing often embarrassing changes as they transition from childhood to adulthood”—their periods, in other words. According to the filing, some girls avoid going to the bathroom to avoid sharing it with the transgender student, “thus risking certain health problems”; they wear their gym clothes under their regular clothes so they never have to be naked at school; or they’re late for class because of the time they spend looking for an empty restroom.