"Birth abroad to one United States citizen"For persons born between December 24, 1952 and November 14, 1986, a person is a U.S. citizen if all of the following are true (except if born out-of-wedlock)[8]:
The person's parents were married at the time of birth
One of the person's parents was a U.S. citizen when the person was born
The citizen parent lived at least ten years in the United States before the child's birth;
A minimum of 5 of these 10 years in the United States were after the citizen parent's 14th birthday."
Mr. Obama was born in 1961 in Kenya/Hawaii/wherever to at least one U.S. citizen who was married at the time, therefore Obama is a U.S. citizen.