I am going to share this because it is one of my most favorite annecdotes regarding my kids and race.
Some background...my son "R" is my bio son, and my daughter "D" is African American and was adopted at age 6 domestically. R and D are in the same class as school...both in second grade now.

Last year, they were both in first grade and D was still a fairly new addition to the family. One day the kids had a substitute teacher. She was reading the role and saw the name DH and saw a little black girl, and then saw the name RH and saw a little blonde boy. Then she noticed them playing together all day and interacting lots. Finally, curiousity got the better of her and she pulled R aside.

substitute teacher- "So....R...are you and D....ummmmm......related or something?"

R- "DUH! Can't you see she's my sister?????"

Got to love it! The teacher actually called me to apologize for "offending" R. Now, I don't endorse the use of the word "DUH", but I was really touched to see how quickly the kids bonded and claimed each other as siblings. The teacher said that R honestly couldn't tell what her problem was and why she couldn't see that D was his sister.

Why can't we all be like 6 year olds????