An effort to repeal California's first-in-the-nation transgender student law has failed.

The law, known as the School Success & Opportunity Act, requires public schools to allow transgender students access to the restroom and locker room of their choice. Those students can also decide what sports they want to play.

Supporters said the law will help reduce discrimination faced by transgender students.

A coalition of conservatives formed the Privacy for all Students campaign to put the measure up for referendum in November.

The group needed at least 504,760 signatures to force a public vote on the law. According to the secretary of state's website, opponents of the law submitted 487,484 valid signatures.

In an email to supporters, the group's Karen England insisted “it's not over” and vowed to return to court, if necessary.

“We are preparing for the next stage of the battle,” England said. “After months of waiting, we now get to see why so many signatures were thrown out. Certainly some signers were not registered to vote or had moved without changing their address. But it is also certain that many of those signatures were rejected based on reasons that will not survive a legal challenge.”

The San Francisco-based Transgender Law Center described the law as necessary to ensure “that schools have the guidance they need to make sure all students, including those who are transgender, have the opportunity to do well in school and graduate.”

“This law gives schools the guidelines and flexibility to create an environment where all kids have the opportunity to learn,” Transgender Law Center Executive Director Masen Davis said in a statement. “We need to focus on creating an environment where every student is able to do well and graduate. This law is about doing what's best for all students – that's why it's supported by school boards, teachers and the PTA.”