Brennan Linsley / AP file With her face reflected in a mirror, Coy Mathis, left, a transgender girl, plays with her sister, Auri, 2, center, at their home in Fountain, Colo., on Monday, Feb. 25, 2013. Coy's parents are suing the Fountain-Fort Carson School District 8 after she was denied access to a girl's bathroom at her elementary school.