The idea or ideas is Alice being the human and becoming pregnant with her and Jasper's human/vampire hybrid. The other one Rosali and Emmett before the volturi confrontation finds Alice,Jasper and there daughter to prove human/vampires aren't threats.
If you read my profile, you will see I am not just saying that. I wish I had more "Alice" in my personality! I love how she is just sooo free to be herself and there is nothing anyone can do but just love her as she is. It seems to me that is how it should be.