Race - A classificatory term, broadly equivalent to subspecies...Though the concept is a very commonly used one, it has been largely scientifically discredited. The consensus among social scientists today is that race is a social construction, rather than a genuine biological category...Human populations constitute a genetic continuum where racial distinctions are relative, not absolute...
With the advent of mental testing as a means of attempting to measure intelligence, the concept of race became more controversial, with some researchers claiming that, because some groups of black children have performed badly on tests, they are genetically inferior to whites. Critics of this notion point out that intelligence and other 'mental' tests are designed from a white, middle class perspective that is skewed towards one group and will inevitably lead to poor performance by the other.
(Fontana Dictionary of Modern Thought, 1999)
All I'm saying is, if you think 'race' is a useful classification to describe differences between us then sometimes that's not neutral. It can also be used to ascribe superiority and inferiority between groups, which is all the more fixed and intractable because, after all, it leads to ideas like...
your type haven't the intelligence of 'my race',
your race is not as civilised as 'my kind',
I can tell just by looking at you that your inferiority to me is racial/ biological.