With children rejecting the birth gender at younger ages and the transgender rights movement gaining momentum, schools in districts large and small, conservative and liberal, are working to help transitioning youth fit in without a fuss.
California this year became the first state with a law spelling out the transgender student rights in public schools, including the ability to use restrooms and to play on sports teams that match their expressed genders.
Another 13 states prohibit discrimination on the basis of gender identity in schools. Dozens of districts, from Salt Lake City and Kansas City to Knoxville, Tennessee, and Decatur, Georgia, have adopted similar protections.
Parents are increasingly seeking a comfortable learning environment for their transgender children, according to Transgender Legal Defense and Education Fund Executive Director Michael Silverman.
His group represented the parents of a transgender Colorado grade school girl who was prevented from using the girl's restroom until state civil rights officials ruled in her favor last year.
There's "a new generation of parents who grew up in the age of the gay rights movement and are saying, 'We want to do what is best for our children,'" he said.
The trend is likely to accelerate with help from the federal government.
Last month, the U.S. Education Department alerted districts in a memo on sexual violence that it would welcome civil rights complaints from transgender students under Title IX, the 1972 law that bans gender discrimination at schools.
The guidance gives families new leverage to negotiate access to locker rooms, sports teams and other kinds of accommodations covered under California's law, said Mark Blom, a National School Boards Association attorney.
He said the memo surprised him because courts have said Title IX doesn't provide protections for sexual orientation or gender identity.
"It's going to create a real problem for school districts because the department has the right to go in and attempt to require the district under threat of losing federal funding to meet the standard the department articulates," Blom said.
School officials in states without anti-discrimination provisions for transgender residents already have been grappling with how to serve students whose needs conflict with traditional views about when and why boys and girls are separated.
The ACLU of Mississippi got involved last year when a high school senior who was born male but identified as a girl wanted to dress accordingly. The principal balked, saying the dress code required clothing to conform to gender.
The school board relented and stood by its decision, even after some parents and students complained, said Bear Atwood, then the state ACLU's executive director.