In 1983 when my son was born at Ft Belvoir my wife was working for the German Govt in D.C. and my wife was told that he was also a German citizen, so my son got duel citizenship. We checked Immigration and Naturalization to see if this was correct and were told by INS that since he was born in the U.S., even if we both had been German he would be also considered to be a U.S. citizen until he was 18 then he would have to have declare which citizenship he would denounce. When my son turned 18 he denounced his German citizenship. I don't know if this has been changed, but I believe that it is still in effect. You are considered to be a U.S. citizen if born in the U.S.