The longer a child looks at a face indicates the child's preference for that particular face. The Caucasian Israeli infants looked longer at the Caucasian faces than the African ones. The African Ethiopians looked at African faces longer than at Caucasian faces. If the African Israelis exhibited a preference for African faces, the role of nature in own-race face bias would have been shown. However, the African Israeli infants showed no preference for the Africans or the Caucasians. This data shows that nurture plays a significant role in race face perception.
This study shows that our environment greatly influences our perceptions. Even infants at 3 months of age demonstrate signs of racial preference, but this preference is limited to the race they are mainly surrounded by. Heightening cross racial contact mitigates the effects of the bias. Is the own-face race bias a problem? Perhaps: the bias signals a lack of diversity in surroundings. The influence of the own-race face phenomenon may carry over into our daily perception and can cause some racial prejudice beyond our direct control.
It's true that the study is not willing to entirely discount own-face bias. But the actual findings it received did not show an own-face bias. The nurture effect appears to greatly outstrip whatever own-face bias there is.
So there would, in fact, seem to be a way to help avoid raising racist children (or at least severely mitigate one source of racism): raising children in diverse surroundings. That's what the study recommends, and that's what us crazy liberals have been recommending on race relations for decades now.
The study is Bar-Haim, Y., Ziv, T., Lamy, D., Hodes, R.M. (2006). "Nature and nurture in own-race face processing." Psychological Science, Vol. 17, 159-163.