FREMONT, Calif., June 7 — The trappings of a typical high school prom were all there: the strobe lights, the garlands, the crepe pineapple centerpieces and even a tiara for the queen. In fact, Fatima Haque's prom tonight had practically everything one might expect on one of a teenage girl's most important nights. Except boys. Ms. Haque and her friends may have helped initiate a new American ritual: the all-girl Muslim prom. It is a spirited response to religious and cultural beliefs that forbid dating, dancing with or touching boys or appearing without a hijab, the Islamic head scarf. While...