Sibling will b advantage if both r same gender. I am telling this from my exp. Siblings wont hv diff. till they get married and move out of house. I see girls sibling keep constant touch with each other after marriage and share parent responsibility. Same with boys siblings. cobrothers are much better than cosisters. If boy and girl then their bonding s only till their marriage, after they see each other only on occasion Brother will help financially, but no emotional support. my cosister and sil hv sister. i hv seen hw they bond with, whereas me and brother hv no such emotional bonding. My only happiness s i hv two daughters who will eachother.