Utah- The state is fighting a challenge to a new Utah law that requires Internet service providers to give customers a way to block porn sites.

Attorney General Mark Shurtleff filed a motion in federal court Wednesday to dismiss a lawsuit submitted on Nov. 17 by the “Free Speech Coalition,” a trade association for the adult entertainment industry.

The coalition contends the Utah law, which took effect in July, violates the Constitution’s guarantee of free speech and unreasonably increases the cost of conducting business across state lines. It also contends the law’s definition of objectionable material is too vague to enforce.

Shurtleff contends the First Amendment does not allow pornographers to send materials to parents and children once they have asked not to receive it.

“By challenging our Child Protection Registry, they have proven their real intent to force smut on our children in our homes and schools,” Shurtleff said.

The Utah Child Protection Registry allows parents to sign up their children’s e-mail addresses to block advertising for pornography, illegal or prescription drugs, alcohol, tobacco, gambling, firearms and fireworks. Registration is free.

If an e-mail address is registered for 30 days, the law forbids sending the address a message that “advertises a product or service that a minor is prohibited by law from purchasing; or … contains or advertises material that is harmful to minors.”

More than 200 senders of potentially offensive material have agreed to comply, according to the state attorney general’s office.

Assistant Attorney General Thom Roberts is defending the state against the lawsuit. The registry will continue operating pending a ruling.