Frankly, it doesn't really matter to me who his biological father was. His mom wouldn't be the first woman in history to sleep around, and it's ridiculous to blame children for the actions of their mother (or father for that matter).
What saddens me about President Obama? His ideology helps create more single mothers by subsidizing single motherhood and immorality. It's fact. The children of single mothers are significantly more likely to be dysfunctional themselves.
He does look like Marshall in that pic, but I really do not think Marshall is his biological father. When I saw Dinesh D’Sousa’s (sp?) movie last year, seeing Obummer’s half-brother in Kenya being interviewed convinced me that Obama, Sr., was the real father.
I had not been thinking of the paternity issue; it just struck me as I watched the Kenyan brother. The brother just looked too much like the current infestation in the White House for me to think that Obummer’s father could be anyone else.