Which GOP candidate is the most presidential? Romney’s at least got the most White House DNA. (Win McNamee/GETTY IMAGES)

Romney is related to six former presidents: George H.W. Bush (10th cousin, once removed); George W. Bush (10th cousin twice removed); Franklin D. Rooselvelt (eighth cousin, twice removed); Calvin Coolidge (10th cousin); Herbert Hoover (10th cousin); and Franklin Pierce (sixth cousin, four times removed), according to Ancestry.com.

Former Utah governor Jon Huntsman — who is himself a distant Romney cousin — boasts four of those former White House denizens among his relatives: Roosevelt, Coolidge and both Bushes.

Texas Gov. Rick Perry has only one ex-prez in the family. He’s a fifth cousin, four times removed, to President Harry Truman. (He is, however, a first cousin, six times removed, to colorful Texas Gov. Sam Houston).

We still don’t know whether any of the GOP candidates are related to President Obama — the company says they’ll do more research leading up to the general election.

But here’s a good talking point for those holiday cocktail parties: While Obama and Romney are both distant cousins of the Bushes, it seems they are related through different branches of the family, Ancestry says.

The online family history site looked at the family trees of some of the GOP hopefuls (though they’re still working on Newt Gingrich’s lineage) as a way of highlighting the “surprising” things people can learn once they start tracing their own roots, says Anastasia Harman, the company’s lead family historian.

Previously, Ancestry.com has found that Obama is distantly related to conservative talk show host Rush Limbaugh and former Alaska governor Sarah Palin.

All this familial blood in today’s politics doesn’t necessarily mean more comity — and that should be no surprise to anyone with a large family of opinionated relatives.