Rosalie hated being a vampire. She wanted to be able to move forward in life. To have children, to have grandchildren, but she was stuck at the age she was turned and the possibility for her to have kids was taken from her. Emmett knew she wanted kids, her entire family did. And apparently, so did the universe. It was strange, how it happened. Rosalie had just been feeling off one day. Her and Emmett has been intimate with one another a few weeks prior. She was confused because she was having symptoms of pregnancy. Obviously, this struck worry in Carlisle. The entire family, mostly Rosalie and Emmett, were flabbergasted to find out that Rosalie was indeed pregnant. The family didn't know how it was possible. But Rosalie, she didn't care about the how, she just wanted to have the baby in her arms. Rosalie felt it was a gift from god. That god was rewarding her for being so close with her niece. She didn't care about the details, neither did Emmett. Emmett was just happy that Rosalie finally was. He was ready to raise the impossible child that was gifted to him and his mate. They didn't know at the time that the baby would be human and would grow at the rate a human would. But when they found out, they were sad to know that they would only have a few decades with the child. And Rosalie refused to condemn her baby to the life she has.