Cultural emphasis would be my guess. Some African American families, especially inner city poor families, view sports or music as the only way to make it out of the hood. Education takes a back seat to being a good athlete. There's a view from their stand point that getting a good education and getting a "white collar" job puts them at a disadvantage because they're in the perceived "white man's world" at that point. Of course this isn't a broad statement, as you can never paint a culture or race with a broad brush. There are plenty of African American families who put great emphasis on education, but I feel that since the majority of African American athletes come from inner city areas, cultural emphasis on sports is the main reason.