Oklahoma Gov. Kevin Stitt.
CNN  — 

Oklahoma Gov. Kevin Stitt on Wednesday signed into law a bill that requires students at public schools and public charter schools to use restrooms and locker rooms that match the sex listed on their birth certificates.

The law specifically applies to students in pre-K through 12th grade at public and public charter schools in the state. Transgender students who decline to use the restroom required under the measure would have to use “a single-occupancy restroom or changing room” provided by the school.

The measure, which cleared the state Legislature last week, will take effect immediately because it was passed with an emergency clause. School districts that fail to comply can have a portion of their state funding cut, and could be sued by school parents.

The governor’s approval of the law comes as conservative state lawmakers around the country have pushed more than 100 anti-trans bills this year, with a particular focus on transgender students. Oklahoma has been front-and-center in this effort, with Stitt having signed at least two other bills restricting transgender rights this year alone.

In late March, the governor signed legislation banning transgender women and girls from competing on sports teams consistent with their gender at public schools, public charter schools and public colleges in the state, adding Oklahoma to a growing list of states that have approved such bans in recent years.

And last month, Stitt signed a law that bans nonbinary gender markers on birth certificates in the state.

Advocates have for years worked to combat bathroom laws like the one signed Wednesday, criticizing them as an unnecessary and harmful attack on a transgender student’s humanity.

“By singling out transgender students for discrimination and excluding them from restrooms that match their gender identity, SB 615 discriminates based on transgender status and sex in violation of the United States Constitution and Title IX of the Civil Rights Act,” ACLU of Oklahoma Executive Director Tamya Cox-Touré said in a statement Wednesday evening.

“These violations put Oklahoma at risk of losing hundreds of millions of dollars in federal funding, and harms transgender youth, all to solve a problem that plainly does not exist.”

Young transgender Americans make up a tiny fraction of kids in the US – the US Centers for Disease Control and Prevention has estimated less than 2% of high school students identify as transgender. Health care professionals have said the types of bills Republicans are pushing are likely to further ostracize transgender kids, a group that already struggles with higher rates of depression, anxiety and suicide.

CNN’s Devan Cole contributed to this report.