According to a biographical history of the Obama family, written by Peter Firstbrook, The Obamas: The Untold Story of an African Family (2010), BHO Sr.s good friend Leo Odera said that BHO Sr. learned, while studying in Hawaii, that back in Kenya his wife Kezia was seen out and about, dancing in nightclubs, in the company of other men (page 207). Up to that point, BHO Sr. had remained in touch with his wife and children, via letters; but when he learned from friends in Kenya that Kezia was stepping out, he became, shall we say, disenchanted. He eventually stopped corresponding with his wife altogether when he learned through friends that she was pregnant by another man. He wrote to Odera:
She has disappointed me because she is expecting another child.
Yes, it’s clear that a baby born in Kenya with the last name “Obama” in that time frame could easily refer to another child entirely. And in fact does, since there is nothing indicating that Zero was born in Kenya, especially since his father is not the Kenyan Obama!