I've seen kids, really young kids, refuse to hold hands with someone whose skin color differs from their own. Or some of them don't want to sit at a table next to another child who is of a different ethnic background. It's sad that this behavior occurs in early childhood settings, when children are supposedly innocent and unbiased.
The key word in all of this is, "different." If a child is different from others in any way, he or she is a prime candidate for being teased, bullied or excluded. Children don't seem to value uniqueness, they value sameness. Again, that's sad. Because we were created to be unique with our own set of talents, gifts and abilities. The only way we should all be the same is in the way we treat others--with empathy, acceptance and love.