At 20, Miley Cyrus has been working in show business for more than a decade. The singer/actress has gone from being a fresh-faced preteen to a platinum blonde vixen -- one who could be headed down the aisle soon with fiance Liam Hemsworth. 
Selena Gomez's appearance hasn't changed dramatically since she starred on the Disney Channel's "Wizards of Waverly Place" in 2007, but her work sure has. Now 21, Gomez has stretched herself with more mature content, such as the risqué movie "Spring Breakers" and her suggestive new single, "Come and Get It." 
Alyssa Milano, who starred as a pre-teen on the '80s series "Who's The Boss?," thinks talent is one factor that helps a child star safely transition into more adult roles. 
Seven years ago, Jaden Smith was a baby-faced child star appearing with his dad Will in 2006's "The Pursuit of Happyness." Although he's once again starring with his father in this summer's "After Earth," teenaged Jaden isn't a kid anymore. 
Along with her older brother Jaden, 12-year-old Willow Smith has blossomed since she first appeared alongside dad Will in his 2007 film, "I Am Legend." The actress and singer showed a more mature look this spring at the May 2013 premiere of "After Earth." 
Vanessa Hudgens came to fame as a Disney Channel star in 2006 but soon stepped away from her wholesome "High School Musical" roots. This year, the 24-year-old is appearing in more adult projects, such as "Spring Breakers" and "Machete Kills." 
It's still hard to believe that Rudy Huxtable is now 34 years old. Keshia Knight Pulliam, the actress who played Rudy on "The Cosby Show" from 1984 to 1992, grew up on TV but acted sporadically since then. This year, she took a dive into reality TV with ABC's competitive diving show, "Splash." 
Macaulay Culkin turned a scream and an exaggerated expression into a blockbuster movie franchise when he starred in 1990's "Home Alone" at the age of 10. He went on to co-star with in 1991's "My Girl," but has in later years not been a huge fan of being on camera. In April, he ripped into paparazzi in the UK for trying to take his photo. 
Along with Knight Pulliam, Raven-Symone is one of the most recognizable child stars, thanks to her work on the long-running "Cosby Show" and her subsequent career on the Disney Channel. The actress has been in the business since the age of 3, and most recently appeared on ABC Family's "State of Georgia." 
"Mad Men" fans have watched Kiernan Shipka grow up as Sally, the daughter of protagonist Don Draper. Having starred on the series since she was 7, Shipka's gone from being a little ballerina with a lisp to a teen girl with enviable poise over the series' six seasons. 
One minute, Abigail Breslin was a 10-year-old "Little Miss Sunshine," and the next thing we know, she's flashing her bra in 2011's "New Year's Eve." The now 17-year-old is grownup enough to take on the older sister role, as she will in the November release, "Ender's Game." 
Along with Vanessa Hudgens, Zac Efron was just a teen when he became famous with Disney's "High School Musical." Now 25, Efron caters to audiences well past high school, such as his turn in Lee Daniels' 2012 film, "The Paperboy." 
Mary-Kate and Ashley Olsen have been in the entertainment industry since they were literally in diapers -- the pair took turns playing the youngest daughter of the Tanner clan, Michelle, on "Full House" from 1987 to 1995. They went on to star in their own movies, but these days the twins are better known for their fashion lines, Elizabeth and James and The Row. 
Best known for his role as Renee Zellweger's cute-beyond-words son in 1996's "Jerry Maguire," Jonathan Lipnicki is now old enough to play Zellweger's love interest. According to IMDb, the 22-year-old has a dramatic film arriving this year starring Christopher Mintz-Plasse called "Tag." 
Chloë Grace Moretz was a "Kick-Ass" actress even as a kid, starring in movies like "The Amityville Horror" at age 8. Now 16, Moretz has ditched the Shirley Temple curls but not her action moves -- the star will appear in the sequel to 2010's "Kick-Ass" this August. 
Dakota Fanning has appeared in so many movies and TV shows since her career's launch around age 6 that we could put together her baby book. Now 19, Fanning is not only an acclaimed actress, but also a high school graduate. 
Daniel Radcliffe's development has been watched by millions as he came of age in the "Harry Potter" movie franchise, which launched when he was 12. By 2007, Radcliffe was ready to show how grown-up he'd become and starred in "Equus" in London -- a stage production that required some nudity. 
Along with her "Harry Potter" series co-star Radcliffe, Emma Watson's racking up proof that she's not little Hermione anymore. The 23-year-old actress plays a thief in this summer's "Bling Ring," and an ax-carrying marauder in Seth Rogen's comedy, "This Is The End." 
Angus T. Jones wasn't yet 10 when "Two and a Half Men" first premiered on CBS in September 2003. A decade later, the now adult actor is ready to break away from the sitcom -- one that he's publicly said he finds distasteful -- and won't be a regular star on the 11th season this fall. 
Justin Bieber is only 19, and, according to his mentor Usher, is still in the midst of growing up. But between the tattoos, the ab workouts and those reckless driving accusations, Biebs is not the same "Baby" singer we met in 2009. 
Amanda Bynes began working at 10, and by the time she was 14 had starring roles on two Nickelodeon shows. Yet around age 24, Bynes ceased her steady work schedule and claimed she was "retired." Lately, that "retirement" has translated into troubling run-ins with the law. 
Lindsay Lohan showed acting prowess at 12 when she played a set of identical twins in the 1998 remake of "The Parent Trap." Lohan went on to star in movies like "Freaky Friday" (2003) and "Mean Girls" (2004), but her tumultuous private life soon interfered with her career. 
Anna Chlumsky became a star at age 11 thanks to her role in 1991's "My Girl." After sporadic appearances on TV, the now 32-year-old, who's expecting her first child this year, has landed a hit comedy with HBO's "Veep." 
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- Many parents worry about the impact of Cyrus' performance on her young fans
- Cyrus' VMA show another example of the sexualization of young girls, said some parents
- Others argued that kids should not have been watching the VMAs in the first place
- One upside to Cyrus' VMA appearance is that it may show strength, said one mom
Editor's note: Kelly Wallace is CNN's digital correspondent and editor-at-large covering family, career and life. She's a mom of two girls and lives in Manhattan. Read her other columns and follow her reports at CNN Parents and on Twitter.
(CNN) -- My list of reasons why I'm glad my girls, ages 5 and 7, were too young to ever get into "Hannah Montana" grew exponentially longer after Miley Cyrus' unforgettable "twerking" in a bra and undies at MTV's Video Music Awards.
"Miley, what exactly were you thinking?" pretty much sums up the sentiment I heard from outraged moms and dads around the country who believe Cyrus, whose loyal fan base includes a huge chunk not yet old enough to drive, should know better.
"It's a damn shame that Miley is doing this to herself, making a vulgar joke out of her talents and her beauty, but it's a much bigger shame that she's doing it to her young fans and other young people (who) see her in the media," said Heidi Cardenas, a mom of two teenage boys, in response to a request for comment on CNN's Facebook page.
"It's the same thing as going to any street corner in America and selling herself for money," said Cardenas.
"I have to instantly think that Miley does not either a) care what her younger fans think of her or b) hasn't even bothered to think of what her actions (are) doing to her image," said Larene Grady, a mom of two whose tween was "absolutely infatuated" with Cyrus but isn't anymore.
Watch Miley Cyrus' shocking VMA act 
Miley Cyrus became a household name for families when her Disney Channel television show, "Hannah Montana," premiered in 2006. Cyrus, now 20, quickly rose to pop star fame and has been changing her appearance ever since. Here the singer attends a July 12 event in Los Angeles. 
The future pop star with her father, Billy Ray Cyrus, in October 1994 in Memphis, Tennessee. 
The father and daughter team make a New York appearance for the Disney Channel in February 2006. 
Cyrus performs during the Radio Disney Totally 10 Birthday Concert in July 2006 in Anaheim, California. 
Cyrus appears at the 2007 American Music Awards in Los Angeles. 
Cyrus arrives at a film premiere in Hollywood in January 2008. 
Cyrus performs for ABC's "Good Morning America" at New York's Bryant Park in July 2008. 
Cyrus appears at the Nickelodeon Kids' Choice Awards in Westwood, California, in 2009. 
Cyrus and her mother, Tish Cyrus, at the 52nd Annual Grammy Awards in January 2010 in Los Angeles. 
Cyrus performs at a music festival in June 2010 in Arganda del Rey, Spain. 
The singer arrives at the 2012 Billboard Music Awards in Las Vegas in May 2012. 
The grown-up Cyrus performs during the "VH1 Divas" concert in Los Angeles in December. 
Cyrus shows off her moves with Robin Thicke during the 2013 MTV Video Music Awards in Brooklyn, New York, on Sunday, August 25. 
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Photos: Evolution of Miley Cyrus 
From teen queen to all grown-up "She thinks Miley does not appeal to children (who) used to like her as 'Hannah Montana,' which speaks volumes coming from a 10-year-old who had two 'Hannah Montana' parties, everything from bed sheets, pajamas, bath soaps, toothbrushes and book bags," Grady added, also in response to a tout on CNN's Facebook page.
Miley Cyrus twerks, stuns VMAs crowd
"Hannah Montana" seems about as relevant to the current day Cyrus as a typewriter is to millenials.
The 20-year-old has every right to chart a new course beyond her Disney days, moms and dads said in comments on Facebook and exchanges via e-mail. It's just that the path she is choosing seems so wrong and dangerous, many said.
Sonia Prince of Nashua, New Hampshire, said her kids -- ages 9, 12 and 13 -- will no longer be listening to Cyrus' music. "There is enough fantastic music out there with people who have respectful behavior, especially women who don't feel the need to be sexual in public in order to be successful," she added.
Cyrus' choice to wear next to nothing and strut around the VMA stage is yet another example, frustrated parents say, of the sexualization of our young girls, an issue we touched on at CNN.com just a few weeks ago in our piece on how too many tween fashions are too sexy, skimpy and short.
"I do think Miley wrongly represents the way girls should act today," said Steve, a CNN commenter who shared his first name and the fact that he has a 12-year-old granddaughter.
"The way they dress, act, not caring about how other people may respond to your actions," Steve added. "I think it is an oversexualization of young girls/young women."
Robin Belkin, a mom of three in Northern California, believes Cyrus' performance only adds to the already "damaging image of women-as-sex-objects."
"I just find it extremely discouraging and difficult to hold out hope for the improved status of women in this world when even the most entitled among us so negatively reinforce the worst stereotypes and misogynistic attitudes about women," said Belkin.
Opinion: Miley Cyrus is sexual, get over it
"Her behavior sets 50 to 60 years of women's forward progress back a long way when you consider that her huge fan base really only consists of young and impressionable girls and horny young boys, who, unfortunately on many levels, are our future leaders," said John Rodrigues of Boston, in response to a request for comment on CNN's Facebook page.
Miley Cyrus follows post-child star path 
Miley Cyrus' performance shocks fans 
Critic: Miley gave me nightmares "Growing up under the impression that this behavior is not only OK, but acceptable, is such a terrible message and, in this case, I am happy I'm not a father trying to keep this away from my children," the 35-year-old single Army veteran added.
Eric Solomon, a father of two, watched the VMAs with his 15-year-old son. "I am so embarrassed and sitting next to my son and watching this happen made me even more embarrassed," he added.
Solomon said he has conversations with his sons about what's right and what's wrong, and said that they know Cyrus' performance was "not appropriate" and not the behavior of "your normal woman."
Mary Hogan of Cordova, Tennessee, doesn't have kids but works in education and says parents have a role to play.
"Parents need to explain to their kids that what she did is not OK, and should not be imitated," said Hogan, adding that parents who didn't like what they were seeing should have changed the channel.
"I think the biggest responsibility for a parent is to know what their kids are watching," said Mark Edwards of suburban St. Louis, who has three teenage sons. "The VMAs aren't appropriate for kids under a certain age and if some parents feel discomfort over what was aired, should they have been letting their kids watch the show in the first place?"
"The VMAs are supposed to be shocking," said a woman who did not want to be identified. "Why is Miley Cyrus such a big deal? ... I am more shocked people are watching the VMAs with their children."
Miley Cyrus upholds MTV VMAs tradition
After all, consider VMA highlights of years past when Lady Gaga donned a dress made entirely of raw meat and Madonna and Britney Spears kissed (mouths open!). It was, in fact, at the VMAs years earlier when Madonna broke out onto the national stage with her "Like a Virgin" performance.
Cyrus "took a page straight out of Madonna's playbook," said Ivan Baker, a father in New York City, on Facebook. "I guess I am jaded. Not very impressed or shocked."
While much of the online conversation post-Cyrus' national "twerking" episode was dominated by criticism, there was also a very motherly and fatherly response, parents who worry that Cyrus is a child in need of serious help.
"It's clear that Miley Cyrus' lifestyle as a young woman is expressing pain and is dealing with emotional problems," said Andrew Thompson, an engaged father of two boys in Country Club Hills, Illinois.
"Her mother and father have a responsibility to come to her aid and work out these social issues before it's too late," he added.
Some parents said there was only one upside they could see from the blistering reaction to Cyrus' performance and that is that it may show strength.
"The fact that she doesn't play the victim and shows that girls can be as aggressive and bad in many ways might in some twisted way pave the way for (women) to play in a more level field with men," said Leigh Bordbar, a mom of two from Toronto who said she was personally disappointed with what Cyrus did at the VMAs. "In her performance, she seemed like the one in control and in the driver's seat, which sets her apart from the ways that perhaps Playboy or fashion models portray women."
Nicky Calvert, a mom of two in Marietta, Ohio, sees another positive.
"There is only one good thing that I can say about her performance on the VMAs," said Calvert. It shows her 9-year-old how she "should never act in public."
May I repeat how happy I am my girls missed this one completely.
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