Up to that point my son was oblivious to skin colour and I think most young children are.
I don't think I'd quite say oblivious. I remember when I was a kid, my best friend was half-black/half-white, and his older sister would sometimes come to babysit my sister and I. The first time she did, my sister asked her, "Why do you have mud on your face?" My friend's sister thought that was cute and funny, and sometimes spoke about it throughout the subsequent years (much to my sister's eventual chagrin -- and embarrassment).
But I do think that race often isn't really an issue with young children -- I certainly never saw any hint of it when I was in elementary school. And it's not like kids won't take every opportunity they can to make fun of someone for being different, i.e. insulting the fat kid or the nerdy kid (both of which usually happened to be me

). Race never seemed to be a factor, however. When I got to high school though, I detected subtle (and on rare occasions, not so subtle) racist attitudes amongst some people, and it was more common to see people hanging out with others of their own race more than in mixed groups. It's sad, really -- sometimes I miss the racial harmony that came with the innocence of childhood. I'm not saying I find racism all that prevalent nowadays, but there's no denying it's often present on some level, even if only in the lack of diversity I see in certain groups and places.
I'm sure there are some children who display racist attitudes, though, and in such cases, I would definitely suggest it's learned behaviour, most likely from the parents. Fortunately, that doesn't always happen; in fact, some children will actively choose to reject their parents' attitudes when they become old enough to understand it -- my parents for instance, are definitely non-racist, even though three of my grandparents have been. Sure, that doesn't always happen, but with racism becoming far less socially acceptable over the past few decades, I prefer to hope that more children will choose not to follow in the prejudicial footsteps of some of the people around them.
