"If Chelsea Clinton does something that makes her political and helps her campaign that is more active than simply posing for a picture," he said, "then the press needs to avoid being manipulated and being simply a passive conduit for whatever images the campaign is promoting."
Other candidates' kids are more open in answering questions about who they are.
The very fashionable and very blond daughter of Sen. John McCain, Meghan, a 23-year-old Columbia University graduate, launched her own blog -- unaffiliated with the campaign -- that deals with everything from her fascination with fashion to what it felt like to see her dad win in South Carolina.
On fashion she blogs: "I love that (entertainment reporter Maria Menounos' blog) included my obsession with Dita Von Teese and Chloe Sevigney (one of my biggest dreams would be to raid their wardrobes)."
She also delves into the political from time to time in a way that may earn her father, 72, credibility with younger voters.
She once called Sen. Barack Obama "cute," and wrote this about her father's S.C. win: "Anyone who wants to know should listen to U2's song "Elevation" to understand what it felt like last night."
Matt Romney, 36, the second-oldest of former Gov. Mitt Romney's five sons, points to the "Five Brothers" blog as a way Romney's sons are connecting with voters.
And Craig Romney, who speaks Spanish, put out a Spanish-language ad in Miami this week, urging Hispanic voters in Florida to vote for him on Jan.29.
But with the increased public role, comes increased media attention.
The Romney sons' $100 million trust fund has been bandied about on Internet blogs, and pundits have speculated about what the Romney sons really think about their father pouring $16.8 million of his personal wealth into his campaign.
"I don't ever expect to see any of that anyways. I don't think any of us kids are counting on that money," Matt Romney told ABC News. "If my dad decides to use the money he's made, than we support him."
Matt Romney, a commercial realtor who lives with his wife and four sons in San Diego, said he and his brothers helped to convince their father to run for president.
"We knew what it meant, and we wanted to let him know that we're all in this together."
At 45, Rand Paul, an eye surgeon, is perhaps the oldest child of a candidate to take on a public role. He has been speaking on behalf of his father, Rep. Ron Paul, R-Texas, across the country.
"I've been listening to his speeches since I was 10, so I figure I've got it down pretty well," he joked.
Rand Paul said he would do his part to raise awareness for his father's campaign on primary day in South Carolina, by agreeing to ride with his two sons on the Ron Paul Blimp over Columbia.
But not all of the candidates' children produce favorable headlines.
At 17, Caroline Giuliani, daughter of Republican presidential candidate Rudy Giuliani, got unwanted media attention when it came out that she had joined a Facebook support group for Obama.
The former mayor's strained relationship with his son, Andrew, who is in his 20s, has also garnered headlines in an election when so many of the campaigns highight the candidates' children as speaking surrogates and fundraisers.
The former mayor has told the media and the public at campaign events that his children are off limits.