Romney’s great-grandfather, Miles Park Romney, fled the United States 122 years ago to Colonia Juarez, Mexico to start a polygamous colony there at the direction of the Mormon church in Utah. He eventually had a total of five wives and fathered 30 children, one of which was Gaskell Romney’s, Mitt’s grandfather, who was born prior to the exodus to Mexico. Mitt Romney’s father George was born in Mexico. Twenty seven years after establishing the polygamous colony there, the Mexican revolution drove half of the family back into the states, when George Romney was 5 years old.
When George Romney ran for president in 1968, there were constitution questions regarding his disqualification, as he was not a "natural born citizen". Since his campaign fizzled like a party balloon with a pinhole leak, the issue never reached full litigation. When Mitt was asked about this incident recently, he said that his father assumed that he was allowed to seek the presidency because "his parents were citizens."
Today, more than forty Romneys remain in the Colonia Juarez colony, including Mitt’s cousin Mike Romney. The ‘clan’ has long since abandoned the practice of polygamy and cousin Mike supports Mitts run for President.
This is an excellent article http://www.dallasnews.com/news/politics/perry-watch/headlines/20111023-mitt-romneys-relatives-in-mexico-are-supportive-but-wary.ece