GRAPEVINE, Texas — High school teacher Em Ramser felt her stomach drop when she noticed an empty seat in her second-period English class one morning in January 2021. “You know you get that sudden feeling,” she said, “where you know something is really wrong?” The missing 14-year-old student reminded Ramser of herself when she was that age — unhappy to be at school most days and wrestling with her identity. At the start of the school year, Ramser had asked every student to fill out a form answering questions about themselves, including how they wanted to be addressed. The absent student, listed as a boy in district records, had asked to be called by female pronouns, and by an alternative name: Ren.