At a high school in prosperous Newton, Massachusetts, it’s “To B GLAD Day”—or, less delicately, Transgender, Bisexual, Gay, Lesbian Awareness Day. An advocacy session for students and teachers features three self-styled transgendered individuals—a member of the senior class and two recent graduates. One of the transgenders, born female, announces that “he” had been taking hormones for 16 months. “Right now I am a 14-year-old boy going through puberty and a 55-year-old woman going through menopause,” she complains. “I am probably the moodiest person in the world.” A second panelist declares herself an “androgyne in between both genders of society.” She...