There are physiological differences among the races that are undeniable. Some are due to genetics and some from environment, factors such as diet. One example is that of the top 100 times in the men's 100m dash, 97 of those times were done by men of West African descent. This is not really just coincidence as we proved in a physiology lab I worked in. The muscle tissue of men of West African descent are shorter fibers than any other group. Short fibers use up oxygen very quickly and inefficiently, enabling short bursts of intense energy. Conversely, we found that men of East African descent tend to have very long muscle striation, and use up oxygen very slowly and efficiently. This explained to us why most of the great long distance runners are of East African descent.
There are many well intentioned people who want to deny the obvious because it offends their sense of what should be fair. My wife, who has seen 1000's of babys born, swears that black male babys have larger penis's even at birth, and most of the delivery room people I know would agree.