PORTLAND, Ore. (AP) - The American Civil Liberties Union of Oregon has joined booksellers to challenge a state law restricting the sale or provision of sexually explicit material to children, saying it could affect constitutionally protected material.

The ACLU says the law approved by the 2007 Legislature is vague and could result in parents being charged for providing educational books to their children - or even an older child who gives material to a younger sibling.

As an example, the ACLU cited the 1975 novel "Forever" by Judy Blume, a frequent target of censors because it deals with teenage sexuality.

"A 17-year-old girl who lends her 13-year-old sister a copy of the book and tells her to 'read the good parts' could be arrested and prosecuted," said Dave Fidanque, ACLU executive director for Oregon.

But a spokeswoman for Oregon Attorney General Hardy Myers, who supported the law, says constitutional issues were discussed when it was being drafted and sent through committee.

"And it passed muster," said spokeswoman Stephanie Soden. "We're prepared to defend the law and we're pretty confident in our position."

The goal of the law is to protect children from sexual predators who provide explicit materials to "groom" their victims.

The chairman of the House Judiciary Committee, state Rep. Greg Macpherson, D-Lake Oswego, said the bill was amended to address ACLU concerns "and we thought we had solved the problems but apparently we didn't."

Macpherson, who is running for attorney general, noted there was no issue with a companion bill to make it a crime to solicit sex from teens over the Internet in order to deal with the same problem.

But the law making it a crime to furnish sexually explicit material is too broad and "potentially criminalizes many constitutionally protected providers of sex education materials," the ACLU said.

Booksellers, librarians, community organizations and health care providers are at risk under the law and could face jail time and fines up to $125,000, according to the ACLU.

To add to the confusion, the law allows teenagers - 13 and older - to purchase such books, putting the burden on booksellers to ensure customers are old enough, said Michael Powell, owner of Powell's Books in Portland.

"It says a 13-year-old can legally buy these books, but it's a crime to sell them to a 12-year-old," Powell said. "How do I 'card' a 12-year-old?"

The book store joined the ACLU to file the lawsuit Friday in U.S. District Court in Portland. It names Myers and the state's district attorneys as defendants. 

(Copyright 2008 by The Associated Press. All Rights Reserved.)