A parental advocacy group is imploring local affiliates to preemptively block an episode of the CW network’s hit show “Gossip Girl,” whose ads suggest it will show a depiction of a threesome on air.

Airing such a tryst, which is being teased in an ad as a "3SOME," is "reckless and irresponsible," said Parent Television Council President Tim Winter in a statement Wednesday, especially in light of the show's largely young, female audience. The threesome involves three main characters in the show but they are not identified in the promos.

The PTC has already sent a letter to affiliates nationwide, reminding them that they will “bear the financial burden of an FCC fine should any of the content on the November 9th episode be found to violate broadcast decency laws.”

Multiple calls made by FoxNews.com to CW President of Entertainment Dawn Ostroff were not returned Thursday.

A representative for PTC told FoxNews.com that the organization has not yet had the opportunity to view the episode and are basing their criticism on news reports and the recent round of advertisements from the network.

“We don’t know how it will be depicted yet,” Melissa Henson, the director of communications and public education, told FoxNews.com. “Our concern is really more thematic with respect to the target audience. We know that the show is especially popular with teenage girls.”

"CW has been defending graphic content on 'Gossip Girl' by asserting that they don't target teenagers," Winters said Wednesday. "Such a claim doesn't even pass the 'laugh test."'

CW spokesman Paul McGuire said the target audience for "Gossip Girl" is 18- to 34-year-old women, with a median viewer age of 27 years old. The network had no comment on PTC's complaint, he said.

But Henson says the PTC is standing firm in their criticism, arguing that the depiction of this type of sexual imagery is “breaking new ground.”

“Images of teenagers in sexual scenarios are nothing new. But the idea of a threesome is a fairly new phenomenon that has previously only been associated with adult films," she says. "The network is giving it a sense of normalcy and depicting it as nothing unusual and suggesting there are no particular consequences for this type of behavior.”

Henson argues that psychologists and therapists would disagree: “[Threesomes] not only increase health risks, but can be emotionally and psychologically damaging, so to present it as normal or even glamorous behavior for teenagers is unacceptable.”

This is not the first time the PTC has complained about the sexy prep-school soap, which Winter said is "expressly targeted to impressionable teenagers."

In July 2008, the organization spoke out against a racy marketing campaign for its new season. Ads showed intimate moments between the show's characters (on a couch, in bed and apparently skinny-dipping), accompanied by headlines like "A Nasty Piece of Work" and "Mind-Blowingly Inappropriate."

The PTC asserts that it is a shared responsibility between parents and the network to monitor what kinds of images are released to underage viewers.

“Parents are of course responsible for what children watch on television or online,” Henson told FoxNews.com. “But that doesn’t let the network off the hook. They are using a public resource to send their message out, so they have to adhere to community standards of decency. And it’s very hard for a parent to combat a multimillion dollar ad campaign telling kids to watch specifically because parents say not to do so.”

Regardless, Henson says the PTC will not give up without a fight.

“A lot will depend on what they show on screen. But we will be communicating with advertisers and will thoroughly monitor the episode," she said. "After our review, if we feel it violates FCC standards, we will consider filing a formal complaint.”

The Associated Press contributed to this report.