WASHINGTON – Texas Sen. Rafael Edward "Ted" Cruz was born in Calgary, Alberta, on Dec. 22, 1970, the son of Eleanor Darragh, from Wilmington, Del., and Rafael Cruz, a native of Cuba.

If he's elected president this fall, he would become the nation's first chief executive born outside the United States.

But his foreign birth is raising questions — most notably from Republican rival Donald Trump — about whether Cruz is eligible for the presidency under the Constitution.

Article II says: "No person except a natural born Citizen, or a Citizen of the United States, at time of the Adoption of this Constitution, shall be eligible to the Office of ­President."

Cruz has dismissed it as a "nonissue" and said it is settled as a legal matter that a child born abroad to a U.S. parent is a citizen at birth. Legal experts overwhelmingly agree with Cruz.

But the dispute has raised many questions about this constitutional requirement.

Q: What's the definition of "natural born citizen"?

A: It is not entirely clear because the Supreme Court has never ruled on the issue. But legal experts say a child's citizenship can be determined based on where he or she is born and who the parents are.

Birthplace is the simplest test. The Constitution was amended after the Civil War to make clear, as the 14th Amendment says, "All persons born or naturalized in the United States … are citizens of the United States."

But before that time and continuing ever since, federal law has also said a child's citizenship is derived from his or her parents. Lawyers point to the Naturalization Act of 1790 adopted by the first Congress. It said that "the children of citizens of the United States, that may [be] born beyond the sea, or out of the limits of the United States, shall be considered as natural born citizens."

More recent immigration laws say a child born abroad to an American parent is a citizen by birth, but the phrase "natural born" has been dropped.

Q: If Cruz is nominated, could someone go to court and challenge his qualifications?

A: Yes, but most lawyers predict they will not get far. In 2008, several "birthers" filed suits contesting Obama's qualifications, even though he was born in Hawaii in 1961. Those suits were dismissed.

Q: Has this issue arisen before?

A: Yes, but only as a matter of discussion. Sen. John McCain of Arizona was the GOP nominee in 2008, and it was noted then he was born in 1936 in the Panama Canal zone, where his father was stationed with the Navy. The Republican Party's 1964 presidential nominee, Sen. Barry Goldwater, was born in the territory of Arizona before it became a state.

When Michigan Gov. George Romney sought the GOP nomination in 1968, news stories noted he had been born in Mexico, his Mormon ­parents having fled there.