President Obama has found another long-lost cousin: Scott Brown, the Republican state senator from Massachusetts who won the Senate seat long held by the late Sen. Edward M. Kennedy.

The president and the senator-elect are 10th cousins, according to the New England Historic Genealogical Society.

Brown’s victory Jan. 19 over Democratic candidate Martha Coakley cost the Democrats their filibuster-proof majority in the Senate and may have jeopardized passage of Obama’s top legislative priority -- a healthcare overhaul.

Despite the political chasm that separates the two men, however, Obama and Brown have at least one solid family link.

The New England genealogy experts report that Obama’s mother, Stanley Ann Dunham, and Brown’s mother, Judith Ann Rugg, both descended from Richard Singletary of Haverhill, Mass. He died in 1687 at 102.

Obama descends from Singletary’s eldest son, Jonathan, who later changed his last name to Dunham. Brown descends from Singletary’s other son, Nathaniel.

Brown said of his family ties to Obama: “I’m glad to be in such distinguished company.”

In 2008, the society discovered that Obama is related to seven previous presidents: George H.W. Bush, George W. Bush, Jimmy Carter, Gerald Ford, Lyndon Johnson, Harry S. Truman and James Madison.

It also learned he was related to actor Brad Pitt and investor Warren Buffet.

mdsilva@latimes.com

The Associated Press contributed to this report.