NEW YORK — Could Mitt Romney become el presidente -- or at least, America's first president with a Mexican-born father?

US news reports this week shed light on a little-known side to the leading Republican candidate to take on President Barack Obama: his surprisingly strong Mexican roots.

The wealthy former governor of Massachusetts, who already stands out in the presidential field for his Mormon faith, has kept quiet about his heritage. He does not speak Spanish, according to his press service.

Like other Republican candidates, Romney has made being tough on immigrants a big part of his platform. But family ties mean that Romney, 64, could in theory be eligible for Mexican citizenship.

His father, George Romney, was born in 1907 en Colonia Dublan, in the north of Mexico, according to a report Monday on NBC television. The area was settled by religious immigrants more than a century ago.

George Romney returned to US soil at the age of five to escape the Mexican revolution. However, other Romneys stayed behind and about 40 of them, including second cousin Leighton Romney, still live in Colonia Dublan and neighboring Colonia Juarez, the report said.

The report said the Romney clan first went across the border to practice polygamy, a former Mormon custom that was outlawed in the United States.

"He's got a great pioneer heritage starting with people that crossed the plains going from Illinois to Utah, and then on from Utah down to Mexico," said Leighton Romney on NBC.

He says there is nothing difficult about dual allegiance, even if this would be unlikely to go down well on the presidential campaign trail.

"We certainly have a love for both countries. I can sing both national anthems and tear up at both of them," he said. "I think that having two countries that you love and two countries that you can serve or be a beneficiary of their service is a great thing."