If they were "standard" anything, the article wouldn't be interesting.
I really don't think any of you read the article. They aren't telling the kids "Hey, you're not a girl or a boy." They're just not telling people what the gender of their newest born is, and not correcting people when they refer to the two older kids as girls. They're letting them dress and play and explore however they choose.
The comments in this thread about how boys and girls are just different are precisely my point. Not only does it make it painfully obvious that you didn't read the article, but it shows that the children will grow into their "natural" self no matter if the parents tell them that they can only wear clothes that are traditionally for boys. The article alludes to the oldest son going to some sort of camp (or similar-- it doesn't say what it is, exactly), so they are interacting with other children.
Again, I don't really know that I agree with everything they're doing (in fact, I know I don't), but at least read more than the subject before sharing your opinion so this can be a real discussion.
I definitely see bullying being an issue, but it's an issue anyhow for lots of kids. Mixing kids from every different background into one building will just have that effect.