This is factually incorrect. His father was a member of the Luo tribe, which is considered a typical "black African," by which is meant what used to be called Negroid, tribe.
“Mr. Obama is 50% Caucasian, that from his mother. What those who want Mr. Obama to write history by becoming “America’s first African-American president” ignore is that his father was ethnically Arabic, with only 1 relative ethnically African Negro - a maternal great-grandparent (Sen. Obama’s great-great grandparent, thus the 6.25% ethnic contribution to the senator’s ethnic composition.)
“That means that Mr. Obama is 50% Caucasian from his mother’s side. He is 43.75% Arabic, and 6.25% African Negro from his father’s side.
“Put another way, his father could honestly claim African-American ethnic classification. He was the last generation able to do so.”
To be classified as Negro, you have to be 12.5% African. Obama is only 6.25%.
http://kennethelamb.blogspot.com/2008/02/barak-obama-questions-about-ethnic.html