There is some mention in this thread about innate or biological racism.
One thing to keep in mind, genocide occurs in nature. Geno (genome or species) Cide (Extermination). Ants will enslave other ants and indoctrinate through chemical warfare to protect their anthill and queen. Ants, birds, chimps, and humans alike possess the biological kin recognition mechanisms to divide conquer or out-forage other sub-species in order to further their own kind. Essentially, those organisms with weaker kin-recognition mechanism tend to procreate less, and therefore, surviving social creatures tend to possess these mechanisms -- such as humans.
Humans that were best able to distinguish members within their own small gathering bands were more likely to procreate. Thus, modern humans possess these mechanisms. They manifest in comparing ourselves with others and forming association or avoiding them. Racial differences are easily and instantaneously observable, unlike personality traits, creeds, or family backgrounds which play a role in how we form opinions of other persons.
Without thought, a person who looks like us will tend to have a better image in comparison to a similar person who doesn't look like us. I'd postulate, if we were to conduct a study, in which toddlers received no adult interaction in a walled lab area, they would tend to have a more positive association among other toddlers of similar skin tones and facial distinctions.
But, I cannot know this, aside from the MANY ethical issues it would be interesting to observe a study of this nature.
Racism isn't totally manufactured by "society" alone, in fact, society is manufactured by our nature, as well as environment. Environment being, any social interactions, experiences, resources, events in our lives, ect.
If anything, as humans, we indoctrinate each other, in many western societies to prejudge others based on beliefs and lifestyles. Which is more logical than using race as a prejudgement in forming associations, such as friendships, though there are certainly lingering attitudes, consious or subconcious that affect how we approach others. These are more "logical" in that they better serve kin-recognition, since, we tend to have similar vested interests with those who share similar ideals/lifestyles as opposed to race alone.
That is why I do have an issue when coalitions formed by race, sexuality, ect. Then again, political and social structures reinforce social segregation in that blacks or gays tend to have similar vested interests. These shared interests support the idea that innate qualities should govern our prejudgements on forming associations. Thus, leading to more self-elected segregated communities and less social harmonization (rather increased polarity).
Oh know, I promised I wouldn't do a huge ramble on my first week of returning to PC.
Oops, sorry.