Last weekend, DS had family friends invite him on an all day outing. SD wasn't invited. This weekend, DS has been invited to a different family friend's birthday party. Once again, the invitation wasn't extended to SD. Both sets of parents are "my" friends from before DH and I married.
Part of me feels bad for any kid stuck at home while the sibling is out doing something fun. However, I'm not at all going to stop DS from going places with his friends!