Obama’s mother was under 21 when he was born and his father was not a US citizen. That’s why he’s not a natural born citizen.
The US citizenship laws on the books at the time of Obama's birth said that in order to convey US citizenship to a child born of a US citizen and a foreign national, that the US citizen parent had to have lived within the US for a period of ten years, five of those being after the age of 14.
Obama's mother would have had to have been 19 at his birth to confer US citizenship on him, per the law. However, she was 18 at the time of Obama's birth, so couldn't possibly have conveyed US citizenship to him, even if he was born in Honolulu.
If he was born in the U.S. then yes he is.
Berg's compelling theory is that Obama was actually born in Kenya, then flown to Hawaii to be registered four days later, and even later was adopted by Soetero and given Indonesian citizenship, nullifying his previous British Kenyan status. The guy needs to produce his documents. But he won't. Where money is, however, the truth will out, and eventually someone will pay enough money to pry his documents loose. Then the excrement will hit the fan, and it will all be.... Bush's fault.