I have thought a lot about this as well! I am such an impatient person, and found out at 20 weeks with my 2 sons. But part of me thinks it would be less hard to find out gender at birth, becase like you said, you'll be all caught up in the new child, ect. I also thought about finding out at 20 weeks but not telling anyone else (except DH). Or make up an excuse like "the ultrasound tech didn't get a good shot."