first black president

Obama is called  first black president. Big fat hairy deal. There is no such thing as a Black, White, Hispanic, or Asian race. The terminology, although prevalent, has not be quantified. Nor can it be with today's technology. That would require genetic sampling of millions of individuals to determine the make-up of a particular race. If such a thing could be done, it would turn into a taxonomy rather than a few selections on your employment application. It would require thousands of sub-species to exemplify the myriad of arrangements of what is called race.

The problem is that ethnicity is defined in geographical terms by point of origin. Human Beings have been traveling and intermingling for quite some time, millennia in fact. The rate of movement and migration has increased rapidly in the last 400 years and geometrically in the last 100. Human Beings are constantly recombining with people who were geographically isolated centuries ago. This mixing of populations has diluted any possible structure or meaning to the term "race". What specific set of data makes someone Black? I have no idea. Certain large scale tendencies between ethnicity can certainly be found. Blacks have a much greater chance of sickle-cell anemia than do whites. What that means to the individual is uncertain. Environmental and economic factors also play a role independent of race. What is necessary to define one's medical propensity is an identification of the genetic markers for a condition and an understanding of the environmental factors that contribute to its expression.
Having people mark a broad category of race on a page is not a scientific endeavor, but rather a political one. Race defines a plethora of political issues in this country despite the inability to define it. Race is a popular social touchstone, but it is not in any contributing to either healthier lives or better Human relations. To suggest that this information is accurate, meaningful, or rational is to make oneself suspect.