Or perhaps...

Emily made the wish. Suddenly the screaming stopped, but she felt a sharp jab in her stomach. She looked down to see that her own stomach was now distended and she could feel the baby inside herself. She yelled out and Jon came running in. He opened the door and said "Emily, you yelled out like something happened to your baby. What's the matter?" The wish had been made where he couldn't hear it, and so he didn't even remember that Emily hadn't been pregnant before today. But, indeed, Jon wasn't pregnant any more.