Sisters?

Yesterday Layla and I were swimming, and I got out to lay on the pool chair. Layla climbed up on me and kissed the baby (my belly), then laid her head down on it to "give the baby love." After a few seconds she looked up at me and said, "Mommy, baby's a girl." She has a 50-50 chance of getting it right, but she said it so convincingly that I can't help but wonder...