There's a story going around some parts of the US media that Obama wasnt born in the US and so isnt eligible for President. Some of the media have asked him for his birth cert as proof, but it hasnt been forthcoming.
All he's come up with so far is a short certificate which confirms that he was born on a particular day, but not the location - hasnt produced the equivalent of the "long form" of his birth cert. Story seemed to break when a member of the Obama family in Kenya mentioned that they remembered his birth. The story goes that Obama's parents returned to Kenya for the summer when college term in Univ of Hawaii ended. Mrs. Obama booked a flight back to US to give birth, but was refused permission to board the plane because she was in late stages of pregnancy. Obama was born in Mombassa. A few days after the birth, his mother returned to the US and registered his bith [US citizens are allowed register their children, even if born outside the US].
In Hawaii, members of the public do not have access to birth cert records, so cant be verified by looking in the public records - needs to be produced by Obama.