Liason / Getty John Kennedy Jr. plays in the Oval Office at the White House, 1963.

In at least one respect, President Barack Obama is not bringing change to Washington. Just like the Bush administration, and the Clintons, Nixons and Johnsons before that, Obama will oversee a White House unencumbered by male children. In the 80 years before the Obama administration, only the Kennedys brought a boy into the White House.

In some countries, being son-less would be considered a weakness, especially in a leader. British Prime Minister Gordon Brown has two sons. So does Italian Prime Minister Silvio Berlusconi, while French Prime Minister Nicolas Sarkozy has three. Even his Majesty King Letsie III, potentate of Lesotho, has a son. (See TIME's Top Ten Photos of 2008)

American voters apparently have evolved beyond such simplistic notions of what makes a good head of state, but they were not ever thus. In the 19th century, the occupants of the White House had herds of boys. The Lincolns had four. The Grants had three sons and a daughter. The Hayeses had seven sons and a daughter. The Garfields had seven kids, five of them sons. Not all of these male heirs lived in the White House  many died young, or were too old to be living with their parents  but several did.

So why no modern manlings in the east wing? I have a theory, born of careful historical analysis and solipsism: It's impossible to be elected to the White House if you have young sons, because that would mean you have to campaign with them.

Campaigning and raising sons are mutually exclusive. Campaigning requires lots of travel, enormous amounts of time in the public eye and months and months of sitting down quietly listening to the same guy talking while wearing your good clothes. It's like 11 straight months of being in church when you're the preacher's kid  with long car rides in between. It's torture on adults, let alone children. But it's worse for boys. Try this experiment: next month ask your son to be on his best behavior in front of other people, from now until November 2009. See how far you get.

"Boys are generally more competitive, risk-taking and defiant, which makes them less manageable," says Meg Meeker M.D., author of Boys Should be Boys and Strong Fathers, Strong Daughters. And the 24/7 scrutiny of the modern campaign makes every small risky and defiant act a public affair. So if you get a little bored of what dad's saying, because he's dad and you've heard it eleventy million times before, you end up here.

The Obama campaign was noted for its discipline, its rigor and its self control: three things most young boys are not noted for. Of course, Obama didn't take Malia, 10, and Sasha, 7, everywhere he campaigned. But long fatherly absences may make the boys even more likely to be unhelpful. "If dad's away on the campaign trail a lot, [boys'] tendencies towards defiance and impulsivity are exacerbated," says Meeks.

Young girls, on the other hand, can be an asset to a candidate's image. "There's definitely something in the father daughter-relationship that makes being in the public eye much easier," says Meeks. "Girls want to please their mothers and particularly their fathers. Their dads can take their daughters places and do things with them and the girls won't act out."

Yes, some modern Pesidents did have sons in the White House. But none of them had to campaign with them. John F. Kennedy, Jr., was in utero for most of his dad's campaign. The Reagan and Bush sons were already grown by the time their fathers were elected. Jack Ford lived with his parents at 1600 Pennsylvania, but he only moved there when Nixon resigned, not through the crucible of a campaign.

And then there's Roosevelt. Teddy and Ethel moved in with two daughters, Alice and Ethel, and four sons: Ted Jr., Kermit, Archie and Quentin. The White House has been recovering ever since.

"Roosevelt's sons were fantastic scoundrels," says Bonnie Angelo, author of First Families: The Impact of the White House on Their Lives. They would sneak around behind the lamplighter on Lafayette Square extinguishing the lamps he lit. They'd slide down the grand staircase on kitchen trays. "When Archie was sick, his brother Quentin  with the aid of a White House staffer  brought their pony Algonquin up to his room in the elevator to make him feel better," says Angelo. These pranks were tolerated, she notes, because the President enjoyed them more than anyone. "The only thing he stopped the boys doing was shooting spitballs at one of the early presidential portraits."

Jack Ford wasn't even a young man when he moved in, but he still gave his parents agita. On one occasion says Angelo, "he had a young lady visiting him in his quarters when he heard his mother showing Barbara Walters around the residence." He managed to avoid making what could have been television history, but it was a close call.

In tough times like these, it would be nice to have a bit of that harmless White House mischief. And the Obamas are still a young couple. With ready access to government-sponsored childcare. No pressure of course, but would it be too much to ask to give the ol' dice another roll? Maybe you can't campaign with a son, but it sure sounds like fun to try and govern with one.

(See TIME's Top Ten News Stories of 2008)