Romney's grandparents were polygamous Mormons who fled the United States with their children because of the federal government's opposition to polygamy.[1] His maternal grandfather was Helaman Pratt (1846–1909), who presided over the Mormon mission in Mexico City before moving to the state of Chihuahua and who was the son of original Mormon apostle Parley P. Pratt (1807–1857).[2][3] Romney's uncle Rey L. Pratt (1878–1931) would in the 1920s play a major role in the preservation and expansion of the Mormon presence in Mexico and in its introduction to South America.[4] A more distant kinsman was George Romney (1734–1802), a noted portrait painter in Britain during the last quarter of the 18th century.[5]

George Wilcken Romney's parents were monogamous American citizens Gaskell Romney (1871–1955) and Anna Amelia Pratt (1876-1926); they married in 1895 in Mexico and lived in Colonia Dublán, Galeana, in the Mexican state of Chihuahua (one of the Mormon colonies in Mexico) where George was born on July 8, 1907.[1][3][1][6] George had three older brothers and would gain two more brothers and a sister.[7] Gaskell Romney was a successful carpenter, house builder, and farmer who headed the most prosperous family in the colony.[8][9]

The Mexican Revolution broke out in 1910 and the Mormon colonies were endangered in 1911–1912 by raids from marauders,[10] including "Red Flaggers" Pascual Orozco and José Inés Salazar.[11] Young George heard the sound of distant gunfire and saw rebels walking through the village streets.[11][12] The Romney family fled and returned to the United States in July 1912, leaving their home and almost all of their property behind.[1][13] Romney would later say, "We were the first displaced persons of the 20th century."[14]

[link to en.wikipedia.org]

As you can see above, George W. Romney, Mitt's dad, was born in Mexico City and was not born a US Citizen but was born a citizen of Mexico.

Mitt is, therefore, ineligible to be President of the United States by the Senate's own definition:

Section 1, Article 2 of the U.S. Constitution states that only a “natural born citizen” can be President.

In 2008, when the Democrats raised the question of whether GOP presidential candidate Senator John McCain was a natural born citizen, the U.S. Senate looked into the matter and decided McCain is one.

On April 30, 2008, the Senate passed a resolution — that Obama himself had signed — to that effect, “Recognizing that John Sidney McCain, III, is a natural born citizen.” SR 511 states the following:

“Whereas the Constitution of the United States requires that, to be eligible for the Office of the President, a person must be a `natural born Citizen’ of the United States;

“Whereas the term `natural born Citizen’, as that term appears in Article II, Section 1, is not defined in the Constitution of the United States;

Whereas there is no evidence of the intention of the Framers or any Congress to limit the constitutional rights of children born to Americans serving in the military nor to prevent those children from serving as their country’s President;…

Whereas John Sidney McCain, III, was born to American citizens on an American military base in the Panama Canal Zone in 1936: Now, therefore, be it

Resolved, That John Sidney McCain, III, is a `natural born Citizen’ under Article II, Section 1, of the Constitution of the United States.”

In other words, the U.S. Senate defines “natural born citizen” as an individual who was born:
On American soil (which includes U.S. overseas military bases); and
Of parents who were American citizens at the time of the child’s birth.

By that definition, Obama is not a Natural Born Citizen — even if he produces definitive documentary proof he was born in Hawaii — because his father, Barack Hussein Obama, Sr., was a native Kenyan and a British colonial subject who gave his Kenyan citizenship to his son. In fact, by pro-Obama FactCheck.org’s own admission, Obama was a Kenyan citizen until his Kenyan citizenship expired on August 4, 1984 after he had reached adulthood.

[link to fellowshipofminds.wordpress.com]