我这是一稿多投，学术腐败，在法律咨询坛问了，到这里向专家再请教一次
我们从绿卡到公民已经是很久以前的事了。最近发现我们老头老太都有Certificate of Naturalization，但孩子们都没有，当然他们早就有了美国护照。估计当时我们两口子拿到Certificate of Naturalization就去申请美国护照，捎带把孩子们都申请了。
-Your kids' US passport is good enough to prove their US citizenship, so it is not necessary to get the certificate of US citizenship. But if you want to get it, just file N-600 to USCIS. If your kid is over 18 years old now, he/she can file N-600 by him/herself. If your kid is less than 18 years old, then you can file N-600 on behalf of your child. See this link:
Application for Certificate of Citizenship | USCIS
护照经常要renew，如果他们要得到Certificate of Naturalization or Citizenship，具体程序是怎么样的？
普遍认为美国护照也是美国公民证明，但Certificate of Naturalization or Citizenship似乎更正式一点。我有个孩子（成年很多年了）最近目睹了ICE当街抓人，有点胆战心惊，问了Cergificate of Naturalization。我们有些内疚，没在他们未成年时做到底。
-You worry too much.
谢谢！
