I know there are people out there who believe we shouldn't be using the word race at all, and all Humans should just be considered one people. While it's true that we can all breed with each other, and have viable offspring, there are some definite differences between people worldwide. In fact I believe there are three main skeletal structures in Humans, and an expert can tell the difference between mongoloid, caucasoid, and negroid. It's not just skin pigments, though the color of one's skin is one of the most obvious indicators.
The Anis are probably a little too open minded, since there are people their parent's age that are opposed to things like mixed relationships, as well as other things. No one even manetions any kind of awkwardness of a Jewish boy getting intimate with an African American girl, or a group having such a wide range of ethnic differences. Two Jewish kids, a possible white kid, an African American girl, and a Hispanic boy. That's about as diverse as the Planeteers.
There's nothing wrong with it, as being open minded is great. But realistically I think the subject would come up between parents and peers. I'm not from California, but where I'm from that wouldn't happen without at least a few people commenting about it.