NEW YORK — CBS responded to complaints over a conservative group's planned Super Bowl ad featuring football star Tim Tebow by saying that it had eased restrictions on advocacy ads and would consider "responsibly produced" ones for open spots in its Feb. 7 broadcast.

CBS Corp. said Tuesday it had received numerous e-mails — both critical and supportive — since a coalition of women's groups began a protest campaign Monday against the ad, which the critics say will use Tebow and his mother to convey an anti-abortion message.

Funded by the conservative Christian group Focus on the Family, the 30-second ad is expected to recount the story of Pam Tebow's pregnancy in 1987. After getting sick during a mission trip to the Philippines, she ignored a recommendation by doctors to abort her fifth child. She later gave birth to Tim, who won the 2007 Heisman Trophy and helped his Florida team win two BCS championships.

CBS said Tuesday that the decision to air the Tebow ad reflected a change in its policies toward advocacy ads that has evolved over the past several years.

"We have for some time moderated our approach to advocacy submissions after it became apparent that our stance did not reflect public sentiment or industry norms," said spokesman Dana McClintock. "In fact, most media outlets have accepted advocacy ads for some time."

He said CBS "will continue to consider responsibly produced ads from all groups for the few remaining spots in Super Bowl XLIV."

In 2004, CBS was criticized by many liberal organizations for rejecting an ad by the United Church of Christ highlighting the UCC's welcoming stance toward gays and others who might feel shunned by more conservative churches.

CBS said Tuesday that, under its new policies, the UCC ad would have been accepted for airing. The network said that it has run ads in the past year or so with divergent views on topics such as the health care overhaul, climate change and energy policy.

Thirty-second commercials during the Super Bowl are selling for $2.5 million to $2.8 million.

On Monday, a coalition led by the New York-based Women's Media Center, with backing from the National Organization for Women, the Feminist Majority Foundation and other groups, urged CBS to scrap the Tebow ad.

"An ad that uses sports to divide rather than to unite has no place in the biggest national sports event of the year — an event designed to bring Americans together," said Jehmu Greene, president of the media center.