A federal appellate judge sharply questioned a government lawyer yesterday over whether regulators were too zealous in their efforts to protect children from on-air profanity.

At issue is whether the danger that foul language poses to children is enough to justify the Federal Communications Commission’s policing of network television. At oral arguments in a First Amendment challenge to the FCC’s policies yesterday, a lawyer for the commission said the anti-profanity efforts were needed because network broadcasts are easily accessible to children, especially those with television sets in their own rooms.

One judge on the three-judge panel of the 2nd U.S. Circuit Court of Appeals that heard the case, Rosemary Pooler, sharply rejected that argument, calling it “disingenuous.” That rationale was, she suggested, not reason enough “for the FCC to go galloping to the rescue.”

Parents who put television sets in their children’s room seemed willing to shoulder the risk that their child could hear “fleeting expletives,” she said.

“You want to protect those children even when the parents are lax,” Judge Pooler told the attorney for the FCC, Eric Miller.

Judge Pooler’s remarks signaled her skepticism over whether the FCC had a defensible rationale for changing its standard in 2004 over what is indecent language for a network broadcast earlier than 10 p.m. Fox Television Stations, Inc, joined by CBS and NBC, is challenging the constitutionality of the new policy, saying that it both violates the First Amendment and is too vague.

A lawyer for Fox, Carter Phillips of the law firm Sidley Austin LLP, said that networks were now in the position of not knowing in what instances profanity was or was not permissible.

Mr. Phillips told the court that the only constitutional solution was for the FCC to “ban all expletives” or return to the enforcement policy that had long been in place.

One judge on the panel, Peter Hall, tried to test exactly what the FCC’s new policy would or would not allow. What would happen, Judge Hall asked, if a network decided to broadcast clips of past incidents involving on-air expletives as part of a news segment about the FCC’s new enforcement efforts?

Mr. Miller, the FCC attorney, said that the FCC would not object to on-air profanity in that instance.

“It’s not being broadcast to pander or titillate,” Mr. Miller said, in explaining why the broadcast would not be sanctioned. “It’s being broadcast to inform viewers.”