J.L.
I'm in my second pregnancy right now and it's been pretty different from the first, and waalaa, the sex of the baby is different. With my son I had a lot of nausea for the whole first trimester. With my in-utero daughter, I was worried I miscarried because I felt so good. She also requires that I stay very hydrated or I'll feel super sick. He never cared about water, just food. The ultrasound tech asked if we had any hunches and we did think it might be a girl since the pregnancy has been so different; 30 minutes later we found out we were right :P
I think there's a difference between the first and second because you're too busy childrearing the first that you don't have as much time to feel sick. Kind of like how I always feel worse the more I lay around and baby myself :P