I think his name is Barry Dunham and he has tried to hide the fact that his parents were never married, because his father already had a wife in Africa.
Michele sort of gave it away in an interview she did.
Why do you think he cares?
Among other things, his mother spent a fair amount of money divorcing his father--why would she have done that if they weren't married?
More than half the parents in America aren't formally married--so what?
What really happened is that they got married in the winter break between school terms in January-February 1961 (m. February 2, 1961). They went to Kenya to get married because they (or at least Obama Sr.) knew that marriage in Hawaii would constitute criminal Bigamy; marriage in Kenya was legal and in accordance with social norms.
He returned to Hawaii for spring term; she remained in Kenya and got stuck as a result of airline policy at BOAC with respect to late pregnancy. That is why he was born in Kenya.