No person except a natural born citizen, or a citizen of the United States, at the time of the adoption of this Constitution, shall be eligible to the office of President...So... in 2012 ought we ask of the candidates, "Were you delivered by Caesarean section?".
[U.S. Constitution, Article II, section 1; emphasis added]
If so, the candidate is NOT "natural born".
"Be bloody, bold, and resolute; laugh to scorn
The power of man, for none of woman born
Shall harm Macbeth."
"Macduff was from his mother's womb untimely ripped."