The existence of his two daughters would suggest otherwise.
Plenty of homosexuals get married. What about the former governor of New Jersey?
Actually, a lot of homosexual men have sex with women. There are a lot of former homosexuals, too.
It can be learned and unlearned, in a sense.
Obama has just the perfect dysfunctional background for homosexuality. Perfect - mother abandoned him after some years, never had a father other than a short term stepfather, and was very likely molested by Frank Marshall Davis.
Classic textbook homosexual creating background.