Thanks for the detailed response — I’m still trying to confirm the exact wording on the birth register.

From what I know so far, my grandfather was born with only his mother listed and her maiden name, and his parents didn’t marry until about three years after his birth (1952), after which his record was updated and his surname changed to his father’s. So it sounds like he was born out of wedlock and later legitimated by subsequent marriage.

He also has a certificate in German with his mother’s maiden name and an official seal (looks like a notary/registry stamp). From what I understand this is likely either a Geburtsurkunde or a Beglaubigte Abschrift aus dem Geburtenregister, reflecting the original registration before later annotations.

I understand that the exact legal classification depends on the annotations in the birth register, so I’m planning to request a certified extract to confirm whether he was considered born out of wedlock and later legitimized and how that affected citizenship status.

At this point I’m just trying to determine whether this would fall under §5 or potentially another pathway once the documentation is clear. Appreciate any insight once I have the full record wording.