No one seemed to mind the rape joke on the hit crossover episode of Fox's 'Family Guy' and 'The Simpsons'

This weekend's crossover episode of Fox's "Family Guy" and "The Simpsons" has received criticism for a scene where a character uses rape as a punchline for a joke.

The crossover episode has a joke where the punch line is "your sister's being raped." The line appears in Sunday's much-awaited special where Bart Simpson and his family hang around with Stewie and the rest of the "Family Guy" crew, and has already circulated in a trailer for the episode that Fox released online over the summer.

It punctuates a scene in which the incorrigible Bart is instructing Stewie Griffin in the art of the prank phone call. Bart dials the owner of Moe's Tavern and asks whether there is anyone there with the last name Keybum, first name Lee. When Moe calls out to his patrons, asking for a "leaky bum," everyone gets a laugh.

Stewie thinks that's cool, and asks to make his own prank call.

"Hello, Moe?" he says. "Your sister's being raped."

Tim Winter, president of the advocacy group Parents Television Council, said he's a longtime fan of Matt Groening, creator of "The Simpsons," and sought out the trailer when it was released.

"I was blown out of my shoes when I saw the scene with the rape joke in it," Winter said. "It really troubled me."

He said he found it particularly offensive in the context of stories about sexual assaults on college campuses and, most recently, talk about abusive treatment of women by some players in the National Football League. He said when rape is accepted as a punch line for a joke in entertainment, "it becomes less outrageous in real life."

Winter said he wrote to Groening, "Family Guy" creator Seth MacFarlane and Fox in August, asking that the joke be removed when the episode is shown on television. He said he received no reply.

Fox's entertainment division, through a spokeswoman, said it would not comment on the criticism or whether there are any second thoughts about the joke.

Katherine Hull Fliflet, spokeswoman for the Washington-based Rape, Abuse and Incest National Network, said she did not find the line offensive.

"I think the show is making it clear that rape is not funny by how they are positioning the joke," Fliflet said. "It's my hope that would be the viewers' take-away."

RAINN, which says it is the nation's largest anti-sexual assault organization and operates a rape hotline, works with creators in Hollywood to help them depict sexual assault realistically. The group lists actress Christina Ricci as a national spokesperson.

The National Organization for Women didn't respond to requests for comment on the Fox comedies.

MacFarlane brought up the line during a recent interview with Entertainment Weekly, predicting he will get attacked for it in the media. "But in context," he said, "it's pretty funny."

Winter said he didn't think the subject was worth joking about, and said he was particularly concerned about its exposure to younger viewers who may be fans of "The Simpsons," but are not familiar with the "Family Guy" style of comedy.

"We don't mock certain groups because we realize that it is highly insensitive and morally wrong," he said. "Why wouldn't we do the same thing about sexual assault?"

It's not the first time the adult-oriented humor on the animated "Family Guy" has gotten its creators in hot water. Here are some other examples:

-Fox declined to air an episode, "Partial Terms of Endearment," during the 2009-10 season when family matriarch Lois Griffin contemplates an abortion. She was acting as a surrogate for a couple killed in an auto accident before the baby was born. Fox executives said it was fragile subject matter at a sensitive time. The episode was later released on DVD.

-The episode, "When You Wish Upon a Weinstein" was criticized as anti-Semitic by The Forward, a newspaper that spotlights Jewish issues. In it, the character Peter sings a song titled "I Need a Jew." Fox initially declined to air it, and it was shown first on Adult Swim on the Cartoon Network in 2003. Fox then aired it the next year.

-Advocates for AIDS patients criticized a 2005 episode in which Peter was part of a barbershop quartet that dressed in red vests and danced around a man's hospital bed singing a song titled, "You Have AIDS."

-Sarah Palin called the show's writers "heartless jerks" for a 2010 episode in which the character Chris dated a girl with Down syndrome. When Chris asked what her parents did, she replied: "My dad's an accountant, and my mom is the former governor of Alaska." Palin, who had resigned as Alaska governor months earlier, has a son with Down syndrome.

Here's the trailer:

And the review of the episode:

By the way, a new couch gag of the Simpsons is a weird hit!