I was born overseas and my parents had to do a Report of Birth Abroad. I also had to meet with a judge at an immigration court in either D.C. or Virginia when I was 5 years old to get a Certificate of Citizenship (DOJ Form N-560). Granted, this was over 50 years ago; but both my parents were U.S. citizens (my mother is a naturalized citizen) and I was born in a US Army hospital outside Frankfurt (which ironically is now the U.S. Consulate General Office).
One of our boys was born in Germany as well (Landstuhl) over 20 years ago, but for the life of me I can't remember having to do any citizenship paperwork for him when we returned.