More Fallout From Jamie Lynn's Pregnancy

Teen star Jamie Lynn Spears' schoolgirl character on the hit Nickelodeon show "Zoey 101" is the essence of sweetness and sensibility.

But off screen, points out The Early Show's Maggie Rodriguez, the image of Britney Spears' younger sister is now the center of controversy, after the 16-year-old told OK! magazine she's pregnant.

"It's certainly scandalous," TV Guide's Nadine Mendoza told CBS News, "when there has been an image that's been projected on television for several seasons of this studious, intelligent ... driven young woman, who's definitely a role model."

Critics are calling for Nickelodeon to drop "Zoey 101." Some observers are decrying the parenting skills -- or lack of them -- of the Spears girls' mother, Lynne Spears. And the publisher of a parenting book Lynne Spears has been working on has put it on indefinite hold.

Dozens of cable shows compete for the 'tween market, Rodriguez observes. From "The Suite Life of Zach and Cody" to "That's So Raven," "Hannah Montana" to "The Naked Brothers Band," experts say they offer positive messages.

Photos: Britney's Little Sis
One 12-year-old told CBS News, "They're funny. They're not like bad influences."

Because the characters are so wholesome, Rodriguez says, it's a stark contrast when the stars playing them take a negative turn.

Jamie Lynn isn't the first starlet to run into trouble this season.

"High School Musical" sensation Vanessa Hudgens created a stir - and an image problem for Disney -- when nude photos of her appeared on the Web. Another 'tween favorite, Lindsay Lohan, did time in both rehab and jail.

Ten-year-old Marissa Arriaga told CBS News, "It makes me feel kind of bad, because I look up to them, and they do something bad, and I say, 'Well, I can't believe I looked up to them, because they did that.' "

Isabella Cross, 8, said, "When they do bad things like that, and stories I hear, I just don't feel like liking them anymore."

But so far, Rodriguez says, the 'tween audiences is a devoted one. In the latest Neilsen ratings, "Hannah Montana" was among the most popular shows on cable, in the top ten, with more than 4 million viewers. Disney's fourth quarter earnings soared thanks both to that franchise and "High School Musical," which is now moving to the big screen.

And, Rodriguez concludes, with that many young eyes watching, 'tween celebrities have responsibilities well beyond their years.

And what should parents say to their inquiring 'tweens about Jamie Lynn Spears?

On The Early Show Thursday, clinical psychologist and radio talk show host Dr. Joy Browne said parents should take the opportunity to speak to their kids about sex and -- the earlier, the better.