DES MOINES, Iowa — The largest publisher in America and several bestselling authors joined Iowa's teachers union in challenging the state's new education law that bans books depicting sexual activity in schools.

The Iowa State Education Association, Penguin Random House and four authors — Laurie Halse Anderson; John Green; Malinda Lo; and Jodi Picoult — filed the federal lawsuit Thursday. The plaintiffs also include an Iowa parent and several teachers, who say they have been forced to remove books from their libraries and classrooms in response to the law.

The lawsuit is seeking to block the ban on all books from Iowa's K-12 schools that contain depictions or descriptions of sex acts and to have that portion of the law declared unconstitutional for violating the First and 14th amendments of the U.S. Constitution.

“Our mission of connecting authors and their stories to readers around the world contributes to the free flow of ideas and perspectives that is a hallmark of American democracy — and we will always stand by it,” Penguin Random House CEO Nihar Malaviya said in a statement. “We know that not every book we publish will be for every reader, but we must protect the right for all Americans, including students, parents, caregivers, teachers and librarians, to have equitable access to books and to continue to decide what they read.”

It's the second lawsuit filed this week to challenge the ban. The American Civil Liberties Union and Lambda Legal filed suit Tuesday on behalf of eight Iowa students and their families, as well as Iowa Safe Schools, a nonprofit that advocates for LGBTQ students.

The ban went into effect this fall after it was passed by the state's Republican-led Legislature earlier this year and signed by Gov. Kim Reynolds in May. The law also prevents teaching about sexual orientation and gender identity from kindergarten through sixth grade and requires school districts to inform parents if a student asks to use different pronouns at school.

Reynolds has said the law gives parents more control over their children's education and removes "pornographic" books from schools. Beginning Jan. 1, educators who fail to remove books from their classrooms or libraries will face penalties, including written reprimands and possible license suspensions.

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Lawsuit has 'laser-like' focus on the First Amendment, attorney says

The latest lawsuit has a narrower focus than the case filed Tuesday by the ACLU and Iowa Safe Schools, which challenges several aspects of the law.

Dan Novack, an attorney for Penguin Random House, said the new lawsuit has a "laser-like" focus on whether the law's provision banning books with depictions of sex acts from schools violates the First Amendment, which protects free speech. The suit seeks to have that portion of the law declared unconstitutional.

"It’s not an exaggeration to say that this case will turn upon a very simple question: Does the First Amendment apply in school libraries?" Novack said.

Novack said the government cannot get around the First Amendment "by pretending that school grounds are constitutional no-fly zones."

"The right to speak and the right to read are inextricably intertwined," the lawsuit states. "Just as authors have the right to communicate their ideas to students without undue interference from the government, students have a corresponding right to receive those ideas. Publishers and educators connect authors to students. If the government dislikes an author’s idea, it can offer a competing message. It cannot shut down the marketplace of ideas."

The lawsuit also argues the law's prohibition on teaching about sexual orientation and gender identity before seventh grade violates the due process clause of the U.S. Constitution's 14th Amendment by being "impermissibly vague."

Book bans 'go directly against the ideals of this country'

Schools around Iowa have removed hundreds of books — including critically acclaimed works and many books published by Penguin Random House and by the authors who are suing — from their shelves this year in response to the law.

During a news conference Thursday, Anderson said she's heard from thousands of readers over the years who said her books gave them information they needed to be able to speak up and get support after their own experiences with assault. Anderson's book “Speak” is based on her personal experience of being sexually assaulted as a 13-year-old.

"Readers who haven’t been a victim appreciate the vitally important conversations about consent and about the laws that govern sexual violence — conversations that develop as a natural outgrowth of sharing the book," she said.

Anderson objected to the law's proponents describing books like hers that are removed from schools as "pornographic." "I think that anybody who finds a book about a 13-year-old rape survivor as being pornographic needs some professional help," she added.

Lo's book "Last Night at the Telegraph Club" which won the National Book Award, is a historical coming of age novel about a Chinese American girl who discovers her identity as a lesbian. Lo, who is Chinese American and a lesbian, said there are few works of literature that represent that perspective.

Lo said she and her family immigrated to the United States when she was a child to escape the oppression of the Chinese Communist government.

"When my books started to be banned, it felt to me like a direct attempt to suppress my freedom of speech," she said. "These bans go directly against the ideals of this country."

Banned books:A visual dive into an alarming increase in attempts to restrict books

Book bans continue to escalate in US

Attempts to ban or restrict books in public schools and libraries across hit a record high in the last academic school year, according to reports released by the American Library Association and PEN America earlier this year.

The United States has seen a rise in book challenges over the past three years, which is due in part to the growing climate of censorship and an increase of state legislation targeting certain books in schools.

Recent book challenges have sought to censor multiple titles at once. Before 2020, the majority of challenges were brought forward by a single parent to restrict access to a single title.

From Jan. 1 to Aug. 31, the ALA reported nearly 700 attempts to censor library materials — challenging more than 1,900 "unique" or individual titles. The number of titles targeted marked a 20% increase in unique title objections from the same period in 2022.

The ALA documented the highest number of attempted book bans last year with 1,269 attempts, nearly double the book challenges reported in 2021.

Contributing: Jennifer Borresen, USA TODAY; Samantha Hernandez, Des Moines Register

Stephen Gruber-Miller covers the Iowa Statehouse and politics for the Register. He can be reached by email at [email protected] or by phone at 515-284-8169. Follow him on Twitter at @sgrubermiller.