Stewie Griffin and Bart Simpson Stewie Griffin and Bart Simpson

The Parents Television Council is upset about a rape joke that appears in Sunday's upcoming Family Guy season premiere, in which the Griffin family visits Springfield and meets Homer and the rest of The Simpsons.

The joke, which has been circulating in trailers for the highly anticipated episode, features Bart teaching Stewie the fine art of prank calling. Bart leads by example and calls Moe's Tavern asking for a person with the last name Keybum, first name Lee. Laughs ensue once Moe starts asking for a "leaky bum." 

But then when Family Guy's Stewie gives it a try, he bungles the joke because he doesn't understand Bart's delightfully simple formula. "Hello, Moe?" he says. "Your sister's being raped."

Here's a clip from the episode in case you'd like to see for yourself — the scene in question begins at the 0:47 mark:

According to the Associated Press, Tim Winter, president of the Parents Television Council and a self-proclaimed fan of The Simpsons, wrote to Fox, Simpsons creator Matt Groening, and Family Guy's Seth MacFarlane in August asking that the joke be edited out of the episode. He says he never heard back.

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The AP also reports that Katherine Hull Fliflet, a spokeswoman for Rape, Abuse and Incest National Network (RAIN), did not find the joke offensive, but that she thought the show "is making it clear that rape is not funny by how they are positioning the joke." She continued, "It's my hope that would be the viewers' take-away."

A Fox spokesperson told the AP that the network would not comment on Winter's criticism or whether or not there were second thoughts about including the joke.

It's worth pointing out the episode opens with Peter writing a comic strip that has offended many people, and the Griffins have to leave Quahog as a result.

The one-hour crossover event, which also serves as Family Guy's season premiere, airs Sunday at 9/8c on Fox.