“Obama genealogy” has become even more of a popular hobby than Jewish genealogy. Now, ancestry.com says his white mother’s third generation ancestor may have been a black slave.

The website’s team of genealogists ignored the usual route of tracing the ancestry of Obama’s black father, from Kenya, and instead researched the background of his late white mother, who was from Kansas.

It turns out that the president might be the 11th great-grandson of John Punch, who was one of the first known slaves in the United States, having arrived in 1640 from Africa.

The White House has not commented, but the very subject of President Obama’s lineage is bound to reawaken the “birthers,” who claim that his birth certificate is a fake and that he is ineligible to be president. By law, the American president must have been born in the United States as an American citizen. He says he was born in Hawaii.

Ancestry.com said it cannot be absolutely certain of the slave lineage because there are gaps in the family history, particularly records connecting Punch with a presumed son from an apparent mixed marriage and who was a large landowner. The son is thought to be a man by the similar family name of Bunch, unless the records simply were not transcribed correctly.

The next record in the lineage shows that Punch’s grandson asked the court to marry a white woman, although he was turned down.

One thing is sure – Obama has no Jewish heritage, even though during his 2008 campaign he joked at a Florida synagogue that his name Barack in Hebrew is “Baruch,” which means “Blessed.”