My BIL had his first child a few months ago, their step-couison just had her first child last week. They keep calling the two babies couisons. Thay arn't in my book. Will I then have to call their step-couison Auntie? When we have our first child in a few weeks I don't want to go along with this silliness. I have always got annoyed with this sort of thing, but don't want to cause trouble, so, am I being unreasonable?