UC Berkeley will become the first college in California to build a large-scale gender-inclusive locker room inside its campus gym.

Supporters say that when the 4,500-square-foot room opens next year at the Recreational Sports Facility, it will allow transgender students and disabled students whose aides are of a different gender to access fitness services from which they otherwise would abstain. Men, women and gender-nonconforming individuals will all be able to use the locker room, which will include private changing rooms and lockers as well as partitioned showers and bathroom stalls, campus officials say.

Funding for the $2.7 million locker room comes from a new fee, $54 per student each semester, designed to create more equitable health services that students approved in a 2015 campus vote.

Project plans call for construction crews to carve out space from the existing men’s and women’s locker rooms, so that when it’s completed in fall 2018, the gender-neutral locker room will sit between the two.

“We know we have a lot of students on the spectrum of gender identity and gender expression,” said Trineice Durst, senior associate director of UC Berkeley’s Department of Recreational Sports. “We know from personal stories from students and research across the industry that single-gender restrooms are barriers to access for students.”

In the past, when transgender students needed a private changing area, gym employees would direct them to a single-stall staff restroom, Durst said. The bathroom was not only ill-equipped to meet the demand, she said, but it also didn’t fix a bigger problem: that access to a swimming pool could be reached only by walking through either the men’s or women’s locker rooms.

UC Berkeley’s announcement of the new facility created a mini firestorm across far-right websites, which derided the spending and lamented the school’s liberalism.

The issue of who is allowed in which bathrooms and locker rooms has become a focal point in the battle for transgender rights. President Trump’s administration rescinded Obama-era rules that directed public schools to let students use the facilities that align with their gender identity, not necessar il y the sex they were assigned at birth.

While a host of states have introduced legislation aimed at curbing access for transgender individuals, others have passed bills to do the opposite, such as California’s new law that designates all single-stall restrooms to be open to anyone of any gender.

Some of the fights are now in the hands of the judiciary. On Tuesday, a federal appeals court ruled that a Wisconsin teenager who identifies as transgender can use the boys’ bathroom at his high school. The school district had argued that allowing him to use the restroom would harm other students.

But students who are transitioning or who don’t identify as strictly male or female say that creating gender-inclusive spaces allows them to use buildings and resources free of hostile or discriminatory questions and bullying.

Lucas Waldron, a transgender man who graduated from UC Berkeley’s Graduate School of Journalism this year, said that he was surprised to find the men’s locker room of the Recreational Sports Facility had no private showers or curtains. He never went back after that first experience, and instead paid to use an off-campus gym.

“Safety is the biggest concern for me in gendered locker rooms — especially ones without private changing and showering facilities are extremely unsafe for people like me,” Waldron said. “You just never know if someone might cause a problem if they realize you’re trans.”

Had there been a private changing area and showers, Waldron said, he would have used the gym and pool. Building the new locker room for future generations is a “big improvement,” he said.

UC Berkeley isn’t alone in creating gender-inclusive locker rooms. The University of Arizona broke ground on its own this month, and the National Intramural-Recreational Sports Association — a group that advocates for college gyms and health services — is encouraging its member universities to follow suit.

University of California officials have encouraged their campuses to create gender-inclusive showers, locker rooms and restrooms, too.

Some campuses, like San Francisco State University, have a gender-inclusive shower or changing room area, but not to the size or scale UC Berkeley is planning.

Sasha Buchert, an attorney with the Oakland Transgender Law Center, said a common complaint she hears about gender-inclusive facilities is the inaccurate perception that everyone will be forced to use them.

“Folks in our community frequently experience harassment in gendered restrooms by people who feel like it’s their duty to police the spaces to stereotypical ideas of what a man or woman should be,” she said. “People will decide in high schools or other educational settings that they’ll just skip gym or other activities because of the trauma associated with entering that space.”

Kimberly Veklerov is a San Francisco Chronicle staff writer. Email: kveklerov@sfchronicle.com Twitter: @kveklerov