8老师好！我在2015年以绿卡的身份收养的养子，我2018年获得公民身份。养子在2019年获得绿卡。现在绿卡满五年， N-400申请公民，被拒，理由是：
“On the date you obtained permanent residency, you were 15 years old, and were residing in the legal and physical custody of your father. Therefore, you may have acquired U.S citizenship through your mother as of the date of your approved I-485 application. See section 320 of the Immigration and Nationality Act (INA) and Title 8, Code of Federal Regulations (8 CFR), section 320.2”
“For this reason, we have denied your Form N-400, Application for Naturalization. You may apply for proof of U.S. citizenship by filing an application for a U.S. passport with the Department of State, or by filing Form N-600, Application for Certificate of Citizenship. See section 341of the Immigration and Nationality Act (INA).“
意思是说他在2019年获得绿卡时，就自动获得了公民身份，所以不应该再申请N400。请问真的是这样吗？我查了一下the Immigration and Nationality Act section 320 ，似乎是说小孩可以“Automatic Acquisition of Citizenship”。真的没有想到。特地向您请教。
那他下一步是申请N-600申请公民证书吗？
-Yes if he wants to get his US citiznship certificate.
有什么注意的吗？
-No. Just follow the N-600 Instruction to complete the Form N-600 and prepare the documents.
另外，我看他没有办法直接申请护照，对吗？因为护照要求公民纸或美国出生证。
-He can apply for his US passport now (not have to have the US citizenship certificate). Just bring his green card, his birth certifcate, your adoption certificate, your US naturalization certificate to the local US passport agency to apply for his US passport.
非常感谢您这么多年的无私奉献和热忱帮助！
