I agree with Jennifer O. Why not just continue cosleeping with your baby? Every baby is different, and even though your son was a good sleeper, your daughter is telling you that she has a different personality and different needs. Cosleeping has worked for us with our four girls. We currently cosleep with our 10-month-old. It was the only way that worked for our first baby because she was a fussy baby who would not take a pacifier, bottle or any other substitute for mommy. It was tiring at times, but if she hadn't been that way, I would not have learned to be a patient, selfless parent. My other girls have been very different, more able to self-soothe, but we found that cosleeping was the way to go with all of our babies. We all get more sleep that way, they never have to CIO all alone in a crib, and we transition them to their own bed just before they turn 2. We have not had any sleep issues with any of them. If you need some more help, I recommend "The No Cry Sleep Solution" (and if you choose to let them CIO, try anything other than the "Babywise" method).