This week, a number of publishing houses joined bestselling authors and Penguin Random House in a federal lawsuit contesting an Iowa state law that restricts instruction on gender identity and sexual orientation and forbids the reading of specific works in classrooms.

The “Big Five” US publishers—Hachette Book Group, HarperCollins Publishers, Macmillan Publishers, and Simon & Schuster—announced they will join a case that was first brought in November. Penguin Random House, which owns Sourcebooks in its entirety, also filed a lawsuit.

“We as publishers are uniting in our unwavering commitment to stand with educators, librarians, students, authors, and readers against the unconstitutional censorship measures being imposed by the state of Iowa,” the publishers said in a joint statement.

“The alarming rise of book bans across the country demands our collective action. Now, more than ever, we must stand firmly with our authors and readers to defend the fundamental right to read and the freedom of expression.”

The law, SF 496, was signed into law by Republican governor of Iowa Kim Reynolds last year. According to an earlier CNN story, it mandates that K–12 school libraries only stock books that are considered “age-appropriate” and that any book that contains “descriptions or visual depictions of a sex act” be removed.

The publishers, in conjunction with a number of best-selling authors, Iowa educators, a student, and the Iowa State Education Association, contend in the lawsuit that SF 496 denies students access to literature that “depicts and depicts crucial elements of the human experience” and “prejudices LGBTQ+ perspectives and writers.”

The Iowa statute, according to a news release, aims to “silence LGBTQ+ students, erase any recognition of LGBTQ+ people from public schools, and ban books with sexual or LGBTQ+ content.” Lambda Legal, the ACLU of Iowa, and the law firm Jenner & Block LLP have filed a complaint on this claim.

A federal judge deemed SF 496 “staggeringly broad” and temporarily barred the law’s application in several crucial areas at the end of last year.

Following the judge’s decision, Governor Reynolds declared that “instruction on general identity and sexual orientation has no place in kindergarten” and elementary school classrooms, and she would keep up her “part to protect” children.

“And there should be no doubt that books with sexually explicit content—as explicitly defined by Iowa law—have no place in a children’s school library. It’s absurd that we’re even debating these matters,” Reynolds stated in a statement.

“Why society is so keen on oversexualizing our young children should be the true topic of debate. It’s wrong, and I will keep doing everything I can to keep them innocent.