As a freshman, Frankie Esquer walked into a girls bathroom at Carson High School. All heads turned.She could understand the reaction. From the time she was little, Frankie — her real name is Francesca, but she hates being called that — has preferred dressing in traditionally masculine clothing. She wears her hair short or pulled back, and doesn’t wear make-up.What she couldn’t understand, she said, was the teacher who yelled at her to get out. Then, realizing she’d made a mistake in judging Frankie’s gender, the teacher lectured her on dressing appropriately.“She told me I should pull up my pants, …