I don't have a sister, and growing up I believed it so much better to have only brothers. With brothers, there was no one to steal your clothes or make-up, no one to compete with over friends and boyfriends, and no one to have to share a room with.
But my girls are changing my opinion of sisters. I love watching their bond grow closer with every day and see the many ways they are able to communicate using only one or two words. Watching them, I am now convinced that what every little girl needs is a sister! Someone to dress up with, play dolls with, create mischief with, and giggle with in bed. Someone to help you put on your shoes when you can't quiet figure it out, but don't want mommy to help, and someone to help you when you get stuck on your bike.
The devolpmental gap between them is getting smaller and smaller. They push each other, and compensate for each others weaknesses. And I notice when they are playing games, they seem to use each other's strengths to work together and accomplish things they couldn't do on their own.
They are definitely two peas from one pod!