EVESHAM TOWNSHIP, N.J., Sept. 7 — The children talked among themselves about their parents — children of interracial families, children of divorce, children who had been adopted — and that did not seem to cause a ripple.

“It’s not your fault,” says Montana, a first grader whose parents are divorced.

Emily describes her interracial family — her father is of European descent and her mother’s background is Asian — this way: “It doesn’t mean you have to be a rat to marry a rat. You can be a rat and marry a mouse.”

But at another point in a state-approved educational video shown to third graders here, Daniel introduces his parents: “These are my two dads.”

Another child says, “It’s really cool have to two gay dads, because they brought us into a home, and they adopted us, and they love us.”

That was enough to entangle this wealthy suburb of 45,000, about 15 miles east of Philadelphia, in a heated debate among parents and educators. As the issue simmered, the district decided to shelve the film, provoking the threat of a lawsuit by gay rights activists who said the district’s refusal to show the video was a violation of state antidiscrimination laws.

The issue first arose in December after a class of third graders at the J. Harold Van Zant School here was shown “That’s a Family!,” a documentary created by an Academy Award-winning filmmaker intended to show students the different forms that families can take, as part of the curriculum required in New Jersey. But the district temporarily stopped showing the video after some parents complained that they should be able to decide whether their third-grade children should learn about same-sex couples in the classroom.

School district officials then sought to allay their concerns by providing a special screening for the parents of third graders, although only about a fifth of them attended. A poll conducted for the district found the town divided almost evenly: 50.4 percent were in favor of showing the video, and 49.5 percent were opposed.

After eight months of deliberations, a 27-member committee appointed by the school board and made up of parents, teachers and administrators recommended that the district continue to show the video. But on Aug. 30, the district rejected the proposal and stood by its decision to ban the film.

“I didn’t expect it to come out of Evesham,” Trish Everhart, a member of the parent teacher association at Richard L. Rice Elementary School here, said of the dispute. “I felt like we were living in the ’50s.”

Steven Goldstein, chairman of Garden State Equality, a gay rights group, said the district’s decision, which he called outdated and illegal, was based on antigay prejudice.

“It’s not about parental control, it’s about fear of gay people,” Mr. Goldstein said. “We think the school board’s decision hinges on its fear of one community — the lesbian and gay community — and violates the state’s law against discrimination.”

Mr. Goldstein said his group was considering a lawsuit against the district.

School officials, including Patricia M. Lucas, the superintendent of schools here, declined requests for interviews. But in a statement, they defended their decision and said they would rely on other methods to meet state standards for teaching children about nontraditional families.

“Discussion and instruction on the subject matter involving family diversity will continue in compliance with state core curriculum content standards mandates,” the statement read.

Opponents of the video praised the district’s decision, saying that their position was based not on prejudice, but on what they felt was suitable for their children.

“I don’t think it was appropriate,” said Jennifer Monteleone, 35, who is a parent of two children at the Robert B. Jaggard Elementary School. “If it was maybe in fifth grade, but in third grade they’re a little too young.”

Yet Ms. Monteleone also questioned whether the video should be shown at all because of the presence of the same-sex couples.

“It’s something to be discussed within families,” she said. “I think it’s the parents’ responsibility to teach the kids about that stuff.”

Delores Stepnowski, a parent of another Jaggard student, said parents should have been given more notice that the video would be shown.

“Something that controversial should have been discussed,” Ms. Stepnowski said. The children “shouldn’t learn questionable things in school that they’re not ready for and don’t understand.”