Your kids, how do they get along?
It's so interesting to me how sibling dynamics work. My brother and I would get on each other's nerves so bad, but God forbid anyone else mess with us. We wouldn't have allowed that at all.
My kids get along really well. yes, they irritate each other but overall they have a lot of the same interests and their personalities match well.
I have a few friends whose kids fight like cats and dogs though! There's nothing to it other than they seem to have very different personalities that tend to clash.
How about your kiddos?