HARRISBURG - An offer by a Chick-fil-A franchise to provide lunch at a marriage seminar at a church outside the state capital has touched off a firestorm of protest around the country.

Student and gay-rights groups from New York to Texas are urging a boycott of the national fast-food chain after an outlet in Mechanicsburg agreed to donate chicken sandwiches and brownies for a Valentine's weekend marriage seminar sponsored by a controversial "pro-family" group.

When word got out late last month that the Pennsylvania Family Institute, a Harrisburg-based political advocacy group that opposes gay-rights legislation, was involved with the event (and another later this month in Reading), gay-rights advocates turned on the chicken chain, whose stated mission is to "glorify God" and have a "positive influence on all who come in contact" with it.

"Chick-fil-A is supporting hate by donating to the Family Institute," said Ted Martin, executive director of Equality PA, a statewide lesbian and gay advocacy group.

He said he believes the institute's marriage seminar is about furthering its "anti-gay agenda" and urged its supporters to take action against "deep-fried bigotry."

Michael Geer, the Family Institute's executive director, said his organization is being unfairly targeted as a hate group.

"We are not anti-homosexual," said Geer, who says his office has been deluged with angry calls and hate mail. "We support keeping marriage between a man and a woman."

"They are always saying to us, 'Why not work on fixing your marriages?' So we are. We think the divorce rate is scandalous, and now we are being excoriated for doing a retreat."

The Atlanta-based fast-food chicken chain in the middle of the controversy is unabashed about its religious roots. The privately held company has 1,500 stores nationwide, including more than 50 in Pennsylvania - and none of them open on Sunday.

Its website explains that the Sunday policy is founder S. Truett Cathy's "testament to his faith in God."

Dan Cathy, the company's chief executive officer and the founder's son, issued a video statement responding to the boycott calls, saying that the company "serves all people" and that the donation of food for the Pennsylvania marriage seminars is "not endorsement of the mission, political stance or motives of this group or any other."

Cathy said that while he believes in the "biblical definition of marriage," he accepts anyone's right to disagree and added that the company has no "anti-gay agenda."

He said that while the company supports a marriage retreat center, it has also provided $26 million in general scholarships for young people and does not require store operators to discuss their religious affiliations.

Mechanicsburg franchise operator Brian Gibson, reached by phone, referred calls to the corporate office, where a spokeswoman declined to comment beyond the statements issued by the company.

A student group at Indiana University South Bend was succesful in getting a Chick-fil-A vendor temporarily suspended. (The vendor was reinstated last week after a review by the college president.)

Pennsylvania State University officials said they received one letter signed by three students expressing concern about Chick-fil-A, which provides food for an outlet on campus.

Spokeswoman Lisa Powers said that Penn State handles the hiring at the outlet and follows the university's antidiscrimination policies in operating it. The Chick-fil-A franchisee, she said, provides only the food.

"We feel we are in control of Chick-fil-A product and there has been no attempt by the corporation to impose any of their values," Powers said.

Contact staff writer Amy Worden at 717-783-2584 or aworden@phillynews.com.