Racism: biological or environmental?

I know there is great debate on the nature vs. nurture aspects to racism. I have always been confronted with people telling me that racism is taught to us by others. To raise the question that perhaps we are all racist at birth was a laughable comment (and it pissed people off in seminary). However, in light of the book Why Beautiful People Have More Daughters and this article in TIME, I would like to resubmit that perhaps racism is both biological and environmental.