Keeping up with growing kids is never easy.

And that can be especially true of TV shows whose ratings don't always shoot up as the young stars sprout.

Still, some shows soar by growing with the actors.

ABC's Family Matters, which has watched Jaleel White (Steve Urkel) grow from a nerdy 12-year-old to a goofy man about town, routinely beats its regular competition each week in the Nielsen ratings. Likewise, the ratings for Full House go up, despite the growth spurt of its young stars.

"You have to keep adjusting the material with the changing nature of your cast," says veteran TV producer/actor Sheldon Leonard.

"The best way is to deal realistically with the kind of problems that young people have."

But Fred Fox Jr., supervising producer on Family Matters and a former Happy Days producer, says, "sometimes a series just runs its course."

By its fourth season, Happy Days was No. 1, but after 10 years was out of the top 35.

Likewise, as Fred Savage, the freckle-face star of ABC's The Wonder Years aged, the ratings went south. The show dropped from No. 9 its first year to No. 38 its fourth.

Sometimes, the birth or addition of a new child - like Murphy Brown's Avery; Family Ties' Andrew; and The Cosby Show's twins and Olivia - can perk up an older series by delivering a new generation of plot points.

When Cosby premiered, the Huxtable household included five kids (ages 20, 16, 14, 8 and 5). Over the years, three daughters got married and two had kids of their own.

When Full House made its debut in 1987, the show revolved around a widower, his brother-in-law, Jesse, and pal Joey who shared the duties of diapering baby Michelle ,age 6 months, and rearing Stephanie, 5, and D.J., 10.

By the time Michelle had outgrown her diapers, Uncle Jesse (John Stamos) had become a husband and the father of twin boys. The extended family provided extended material for the show.

Another way to keep the show fresh, says Fox, is to "have the problems grow up with the kids."

The Feb. 10 episode of ABC's Family Matters takes aim at guns in schools when Laura (Kellie Williams) is mugged in the school parking lot.

The 87-year-old Leonard - who worked on both The Danny Thomas Show (1953-71) and The Andy Griffith Show (1960-68) - says success is "dependent upon your ability to observe and . . . to turn what you observe into material for the screen."

The Andy Griffth Show followed the development of a cherubic child named Opie (played by Ron Howard) from ages 5 to 13.

Viewers watched him cope with his first crush; his first fistfight; and death - via a heart-tugging episode about a sling-shot fallen mother bird.

From tot to preteen, Leonard observes, Opie "continues to grow" not only in syndication but in the hearts of baby-boomer viewers.

The adorability factor, he adds, may be the key.

"Casting is of primary importance," Leonard says. "With Ronny Howard, we got lucky.

"There's no way to prescribe intuition or insight," he adds. But if you can't tell, "you don't belong in this business."

I'd like to thank Dirk Oltmanns for sending me this article.