At first my cat, Calista, was a single child. So, she had a very special position in the family (just my husband and myself at the time). My husband cannot stand cats, so she is a symbol of his love for me (he just wanted to shut me up)!
Now she has two siblings, my real children. But her place is still special. She helps me teach my children skills like sharing (taking turns helping to comb her hair), how to be nice (not petting to hard), and how to do chores (helping to feed her). I say it works great since my kids are only 2 and 3 and people can't believe how well they get along and behave.
Calista loves the attention she gets now. At one point I was so bogged down in work that I was completely ignoring her, besides feeding and changing litter. But now my kids can come to the rescue to keep her company. So, having a pet is a win-win.