NEW YORK (Fortune) -- A music-snob acquaintance recently confessed to watching - and voting on - the finale of 'American Idol,' the music schmaltz-fest that aired in May. "I can watch it with my kids," he said, a bit defensively.

He needn't be (completely) embarrassed, though. Part of the reason Idol attracts so many viewers - the season ender pulled in 34.6 million - is precisely because it is the kind of show kids and adults can watch together.

"It is reminiscent of the old days, before TV audiences became so fragmented," says Daryl Evans, vice president of advertising and communications for Cingular, one of Idol's big sponsors. In that way, he says, "It reminds me of the Ed Sullivan Show."

Now other programmers are catching on to the Fox show's sly appeal to families, a trend some on Madison Avenue have dubbed "co-viewing." ("Boy, we can find a cold phrase to describe anything," says Cingular's Evans. "This is just old-fashioned family viewing in my thinking.")

This summer, television audiences have been bombarded by Idol wannabes, relatively wholesome talent contests such as "America's Got Talent," "So You Think You Can Dance" and "Rock Star: Supernova;" and the trend will continue into the fall with the return of "Dancing with the Stars" and "Extreme Makeover: Home Edition."

Perhaps no network has embraced the co-viewing phenomenon as fully as Animal Planet, the pet lover-friendly channel owned by Discovery Communications.

The network "always had inherent appeal to every age group," says Animal Planet executive vice president and general manager Maureen Smith, who joined the network two years ago from the former Fox Family Channel, now ABC Family. "But we didn't have a strategy to capitalize on that."

Indeed, Animal Planet internal research found that 44 percent of its core viewers watched the network with their entire family. In contrast, only 39 percent of ABC Family watchers tuned into the network en famile, and about 28 percent of Hallmark Channel's core audience was "co-viewing" with their families. And so Animal Planet set about creating shows for family audiences, and marketing those programs accordingly.

A recent special on dragons, for example, had content that would appeal to kids and a sci-fi/fantasy element that reached teens and some adult males. But the network sought to reach moms, too, with promos that showed a woman unloading groceries as the shadow of a dragon-like creature flies overhead. "Meerkat Manor," a documentary-style show about a family of the small African mammals, also targets family audiences.

Animal Planet hopes these shows will attract multiple generations of viewers, but it also hopes to woo a different breed of advertiser - not just its traditional advertising base of companies selling dog food and flea collars.

It's surprising that the renewed interest in family programming - by both networks and advertisers (more on that in a minute) - comes at a time when ABC Family seems to be veering away programs that moms and dads can watch comfortably with their kids. (One original series on ABC Family, "Falcon Beach," promotes itself with the tag line: "The first days of summer, the last days of innocence.")

And the shows on popular kids networks such as Nickelodeon, Nick Jr., and Noggin do little appeal to adults. "I want to watch TV with my kids," says Animal Planet's Smith. "I don't just want them to be watching something in their room, but at the same time, I don't want to suffer through kiddy stuff. I'd like to watch something that might stimulate a conversation with my kids."

Many advertisers are hungry for family-friendly shows, too. For one, it is efficient: a marketer can reach many people with a single commercial. And companies derive a sort of halo effect from such advertising.

"It allows them to talk to customers in an environment that mom trusts because it is right for her kids," says Joe Uva, CEO of OMD Worldwide, an ad agency that works with clients that target families, including McDonald's (Charts) and Gatorade.

And while Animal Planet is starting to attract attention from new advertisers seeking to reach families, it is still a bit soon to know if its transformation to a family channel is complete. Meanwhile, according to OMD research some of the top prime time programs for co-viewing are Idol, of course, contest shows such as "Unan1mous" and animated programs such as "The Simpsons."

All of those shows, coincidentally, air on Fox. Who would have thought the network that once brought you "Temptation Island" and "My Big, Fat, Obnoxious Fiancé," would be the new home of family-friendly fare?