C's "babies"

Oh my, C's newest infatuation is with "baby sisters". The mother of our friend/neighbor just had her third baby, a baby sister for her other two girls. C has seen the baby now, not just the talk about her, and she is all about the "baby sister" concept. I keep hearing "I want baby sister," and "where's my baby sister." So far I've managed to convince her that her babydolls are quite enough. The "baby sisters" come with us just about everywhere. They come shopping with us, and they go about the house with us carried, in stroller or in cart. She's very conscientious of their needs: giving them a bottle, covering them with blankets, and making sure they take their naps. It's quite sweet. As for the future and real baby sisters, who knows.