"It's not an easy thing for him. Believe me," Trump said of his son.

In contrast, Trump's adult children, Don Jr., Eric, Ivanka and Tiffany, are sharing the limelight with their famous father. Don Jr. and Eric are running the family business, and Ivanka could end up joining the administration. All three Trump children sat in on meetings their father conducted before and after he took office.

Doug Wead, who wrote a book about the children of presidents, said it's the "ultimate hurt" when the offspring become the vehicle for the ire that some grownups wish they could direct toward the president. He said kids become targets because they're seen as weak.

"Barron can't fight back," Wead said.

Anita McBride, who worked for three Republican presidents and was first lady Laura Bush's chief of staff, said President Barack Obama and his wife, Michelle, did a good job shielding their daughters from most public scrutiny. Bush's daughters were college-bound when he was elected in 2000, so they didn't live in the White House. But their underage drinking made headlines.

"Why in a matter of 24 hours should it be different for this child?" McBride said of Barron.

And Chelsea Clinton said on Twitter that "Barron Trump deserves the chance every child does — to be a kid." But she also added that standing up for kids means opposing Trump policies that hurt them.

The supportive tweet from the former first daughter — who is good friends with Barron's sister Ivanka — shed light on the exclusive club of "first children," who seem to be looking out for one another.

Jenna and Barbara Bush recently applauded Malia and Sasha Obama for surviving the "unbelievable pressure of the White House" and enduring "harsh criticism of your parents by people" who don't know them.

"Take all that you have seen, the people you have met, the lessons you have learned, and let that help guide you in making positive change. We have no doubt you will," they encouraged the Obama girls in a letter. The Bush sisters also wrote a letter to the Obama girls when they moved into the White House in 2009 at ages 10 and 7.

Wead said few tears should be shed over the fact that these children sometimes get rough treatment from the public.

As children of privilege, they are steps ahead of so many of their peers.

"Two of them became presidents themselves," Wead said, referring to George W. Bush, son of President George H.W. Bush, and John Quincy Adams, son of President John Adams.