The Marietta City Schools Board of Education voted to keep a book banned for sexually explicit content out of school libraries, upholding an earlier decision by the superintendent and rejecting an appeal by a parent.

“Flamer” by Mike Curato was removed from the school system’s libraries earlier this year after a parent complained about the content. The Marietta school board then took the additional step to order the superintendent to review all of the books in school libraries — more than 20,000 texts — for sexually explicit material. Marietta parent Kayla Sargent appealed the decision to remove “Flamer” via a process outlined in the board’s directive.

Superintendent Grant Rivera denied her request to reinstate the book in October, which she then appealed to the school board.

“Currently, there are no guidelines or policies that prevent the Superintendent or members of the BOE from arbitrarily determining what is sexually explicit or academically valuable,” she wrote in her appeal. “Without uniformity, you leave room for unchecked bias and discrimination, which is damaging in a district as diverse and multifaceted as our own.”

“Flamer” is a graphic novel set in a 1995 summer camp about a boy who is bullied while coming to terms with his sexuality.

The board voted 6-1 Thursday to deny Sargent’s appeal. They did not publicly discuss the issue.

But it’s not the end for Sargent and a group of parents who also oppose the removal of books from school libraries. They plan to file more appeals and to focus on electing board members who would keep the books available in school libraries. The next election for the Marietta board will be in 2025.

“This book is not staying off the shelves,” she said in an interview with The Atlanta Journal-Constitution. “People are not going to stand for this kind of behavior.”

“Flamer” was also removed from Cobb schools this year for containing “highly inappropriate” content. Cobb will lobby lawmakers this year to establish a rating system for books like the ones that exist for movies and video games.