Can I apply for German citizenship if my father or mother was German at birth?
Due to a new regulation, it is possible in Germany to be recognized as Germans for those who are the son or daughter of
a German.
The nationality of the mother/father at the time of birth is decisive.
In many cases, this person was born in the USA and thus became a US citizen. For example, at the time of birth, the mother was legally a German citizen and the father was a US citizen. After birth, the mother became a US citizen and lost her German citizenship. Today, this person’s son/daughter can become a German citizen through naturalization by declaration and keep the American passport without a retention permit.
Can I keep the U.S. passport after declaratory naturalization?
Yes, it is possible. One can have both passports in such cases.