ATLANTA (AP) — Georgia’s second-largest school district says that it has removed two books from 20 school libraries, saying the books had “highly inappropriate, sexually explicit content.”

The announcement, sent in an electronic message to parents in some Cobb County schools on Monday, comes days after the Republican-majority school board voted 4-3 along party lines to fire a teacher for reading a book about gender identity to fifth-grade students.

Although not new, book removals have surged since 2020, part of a backlash to what kids read and discuss in public schools. Conservatives want to stop children from reading books with themes on sexuality, gender, race and religion that they find objectionable. PEN America, a group promoting freedom of expression, counted 4,000 instances of books banned nationwide from July 2021 to December 2022.

Cobb County, with 106,000 students, said Tuesday that 20 libraries had contained “Flamer” by Mike Curato or “Me and Earl and the Dying Girl” by Jesse Andrews, or both. “Flamer” is a graphic novel about a boy who is discovering he is gay and how he is treated at summer camp. “Me and Earl and the Dying Girl” contains some discussion of sex and a lot of profanity, but is mainly about two high school boys who befriend a girl dying of cancer. Both were among the most challenged books of 2022, according to a list published by the American Library Association.

“Protecting our students from sexually explicit content isn’t controversial, it’s what our parents expect,” John Floresta, the district’s chief strategy and accountability officer. “Our board and superintendent are clear — any book, video, or lesson which contains sexually explicit content is entirely unacceptable and has no place in our schools.”

Jeff Hubbard, president of the Cobb County Association of Educators, said media specialists were being questioned about when they had bought the books and why. Such interviews could be a prelude to the librarians being disciplined or fired. The district didn’t respond to questions about whether officials intended to take disciplinary action.

“They’re scared to death, and one parent complaint could cost them a career,” Hubbard said.

Nan Brown, an advocacy coordinator for the Georgia Media Library Association, said it’s important that students be able to see themselves and others in books. She questioned in particular the removal of “Flamer,” noting Georgia librarians nominated it for a statewide award.

“No book is perfect for everybody all the time,” Brown said. “But that book is really important to some children.”

Hubbard said he fears teachers will feel compelled to censor classroom libraries after the district fired Katie Rinderle. An elementary school teacher, she got into trouble in March for reading the picture book “My Shadow Is Purple,” by Scott Stuart, after which some parents complained. Rinderle said a board policy prohibiting teaching on controversial issues was so vague that she couldn’t know what was barred.

The district didn’t respond to questions about who asked that the books be removed or if the district intends to remove additional books. In an electronic message, which Hubbard said was sent Monday to parents at all 20 schools, the district stated that “With thousands of books purchased over decades, we are making every effort to ensure our library only includes materials that are aligned to Georgia standards, supported by law and CCSD policy, and contain content that is age appropriate for our students.”

Hubbard said the book removals and Rinderele’s firing have been a “train wreck” for morale in Cobb County, which has the state’s highest-paid teachers.

Both Hubbard and Brown questioned whether Cobb County followed its own policies or a new state law laying out how book challenges should be handled.

Cobb County, in response to an open records request by The Associated Press in June, said it had no records of challenges filed under the Georgia law, in effect since Jan. 1. The AP filed a request this month seeking records of books Cobb might have removed without a challenge. The district estimated it would cost $2,822 to produce those records. Some other large Georgia school districts provided records without charge.

Brown said Cobb’s action reminded her of a decision in Forsyth County, another large suburban Atlanta district, to remove eight books in early 2022. After others pushed back, the system put all the books except for one back on shelves. The U.S. Department of Education later warned that Forsyth schools, based on discussions in board meetings, may have created a hostile environment violating federal laws against race and sex discrimination, “leading to increased fears and possibly harassment” among students.