The transgender movement expects Americans to deny the most basic truths about bodily sex and human nature, and whether out of fear or apathy, most acquiesce. But 19-year-old Alexis Lightcap won’t go along. She insists that male and female bodies are different, and that the difference has important consequences for the privacy and dignity of men and women alike. She’s prepared to go all the way to the U.S. Supreme Court to make the point.

Lightcap is one of six student plaintiffs—the only one to go public—in a lawsuit challenging the transgender bathroom policy at Boyertown Area School District, about an hour outside Philadelphia, which allows students to use the bathrooms, lockers, and other private facilities of the opposite sex based solely on their own subjective sense of “gender identity.” Put another way: The school district permits biological boys to enter girls’ private facilities and vice versa.