Chances are if you grew up liking the Beatles or the Rolling Stones, your parents didn't.

And chances are parents today - most charter members of that earlier rock generation - aren't running out to purchase the latest release by Bon Jovi or Def Leppard.

It's called the "generation gap," and the gap is as much a part of America as hotdogs, apple pie and faded blue jeans.

With each successive generation, parents have held their ears, wagged their tongues and lamented the degeneration of society. Then the kids grow up, become as conservative as their parents and repeat the cycle all over again.

Maybe today's parents can't really relate to today's bands, like the Sugarcubes or Metallica. But they can relate to the music of their youth: the Beach Boys, Beatles and Hollies.

For the first time, the parents of today are themselves children of the rock 'n' roll era, and as such they still love rock 'n' roll with the unquenchable passion of their youth.

Only don't look for the old folks at the Top 40 record racks; they're still off buying venerable favorites like "Deja Vu" or "Dark Side of the Moon" or "Sgt. Pepper's Lonely Heart Club Band."

The "aging demographic," as the marketing people call the baby boom generation, has become a national phenomenon. Not only do the members of that generation have plenty of disposable income, but they spend it on video players, compact disk players and an assortment of other expensive gadgetry for enhanced sights and sounds.

Nowhere has the phenomenon been more evident than in the development of "classic rock" radio, a format that features almost exclusively the rock 'n' roll hits of the 1960s and 1970s.

Mike Beck, the FM programmer for Salt Lake City's classic rock station KLZX, calls the familiar tunes "mental collectables" and the "soundtrack of our lives."

"It is the music of our youth, and there are fond memories associated with it. If you liked Buddy Holly when you were 15, then you'll like Buddy Holly when you are 50," Beck said. "We still get a lot of requests for `Satisfaction' by the Rolling Stones. That song was released 24 years ago, yet people still want to hear it a quarter-century later."

There are psychological reasons why today's baby boomers seek out the sounds of their youth. Vivian Seltzer, professor of human development and behavior at the University of Pennsylvania and the author of "Adolescent Social Development, told one writer:

"The adolescent years are when people achieve the last stage of cognitive development. They can abstract on abstractions. Therefore they can deal with music on a much more sophisticated level. It's a subliminal experience of feeling more competent, and a tremendous sense of new power. There is also more power physically, and emotional surges that are experienced intensely for the first time for many people."

Record companies hate the "classic rock" format because they are in the business of discovering new artists, not old ones.

Music critics loathe the format because most aren't old enough to appreciate the memories associated with it.

'80s kids hate it because their parents listen to it.

KLZX station manager Stu Stanick compares the "classic rock" phenomenon to the "Music of Your Life" radio format that remains popular with an even older generation. That format features the music popular just before, during and just after World War II - a period of time wrapped in strong emotions and memories for the parents of the baby-boom generation.

"It's no different for today's parents," Stanick said. "We grew up during the '60s with the Vietnam War and the protests and all. And music was a part of all that. It's the music of our youth, just as the `Music of Your Life' was the music of their youth."

Classic rock radio stations around the country are reporting tremendous success with the format, though experts are mixed on how long the phenomenon will last. In Milwaukee, for example, the classic rock format has been in place four years and is No. 1 in the market. In Salt Lake City, it's fifth in a market of 33 stations and continues to grow every month.

Rock 103, Salt Lake City's dominant album-rock station, also plays a healthy share - at times as much as 50 percent - of classic rock.

What marketing execs are discovering is that the "aging demographic" likes the old music and will pay big money to get it. With the proliferation of the compact disc, record companies have responded (albeit more slowly) with a flood of compilations and re-releases of hits from yesteryear.

In fact, some weeks it seems that there are more re-releases of old material than new records. > It's not just radio and record companies that are tuning in to the baby boomers' obsession with rock 'n' roll. Movies discovered the trend years ago, wrapping a healthy dose of yesterday's hits around the events and experiences of that generation ("The Big Chill," "Platoon").

The phenomenon is even more visible now on television, where programs like "thirtysomething," "The Wonder Years," "Almost Grown," "Tour of Duty" and "China Beach" (and others) all make extensive use of "classic rock" soundtracks. Like the movies, they wrap the music around plot lines that deal primarily with youthful themes recognizable to people now in their 30s and 40s.

Television advertising has relied heavily on classic rock 'n' roll for years, using familiar hits from the '60s to market everything from tennis shoes to cars to hotdogs. Perhaps the most successful campaign of recent years involved the California Raisins - an ad campaign that utilized a sound-alike Marvin Gaye version of "I Heard It Through the Grapevine."

Rock 'n' roll of yesterday is translating into big dollars today. Current advertisers were raised on rock 'n' roll and they like the idea of pitching their products to an old favorite.

Stanick and Beck target KLZX to those 25 to 44 years old - the generation raised during the '60s and '70s. That is also the generation that comprises most of the work force and has most of the disposable income.

"If you're a car dealer, do you want your message going to 15-year-olds who might buy a car someday in the future, or do you want it going to those who can go out right now and buy one?" asked Beck.

Advertisers say they like the format because it specifically targets the audience they are most trying to reach - the audience with the most money to spend. Most KLZX listeners, for example, are married, own their own home and have two incomes.

"We don't have many teenagers listening to us," Stanick said, "and we're proud of that fact."

National studies indicate that a good share of those in their 30s and 40s are dissatisfied with the increasingly hard edge of album-oriented rock and they can't identify with new music of the current college crowd.

And with almost 500,000 people along the Wasatch Front in the age 25-44 demographic, there are a lot of people who are dissatisfied.

"There's a real outcry that today's music isn't real rock 'n' roll," said Beck. "They just can't identify with Guns 'n' Roses or Bon Jovi."> Interestingly, the "modern-country" sound of KKAT Radio appeals to the same demographics as does KLZX's classic rock. Today's country music, with bands like Sawyer Brown, Nitty Gritty Dirt Band and Southern Pacific, sounds a whole lot more like rock 'n' roll from the '60s and '70s than does most of the new material by 1980s rock bands.