My spouse's mother was German and emigrated to the United States in 1958. Until 1975 German mothers did not pass on citizenship to children born in wedlock. When that policy changed there was a process where parents could declare the citizenship of their children born before 1975, but it ended in 1977 and we think her mother never even knew of it.
So my wife was not born a German citizen.
Staatsangehörigkeit § 14
As the result of a court case in 2019, the modern state of Germany decided that this gender discriminitory practice where fathers would pass on citizenship and mothers would not had been unconstitutional. In 2020 an existing discretionary naturalization process called Staatsangehörigkeit § 14 ("StAG 14") was extended with a Muttererlass or mother's redress provision which relaxed some of the requiremens for descendants of German mothers in this circumstance.
We spent much of 2020 gathering documents and conducting genealogical research to prove her mother's German citizenship, as we no longer had the passport. The packet of documentation reached 77 pages altogether. We mailed it in December 2020, and waited. The queue to process applications was several years long.
Staatsangehörigkeit § 5
In August of 2021 while our StAG 14 application sat in the queue, a new and much simpler process to address historic gender discrimination in citizenship practices was introduced called Staatsangehörigkeit § 5 ("StAG 5"). It is a declaration, one declares one's German citizenship and provides evidence that one meets the criteria for StAG 5. The requirements are much simpler and the application is vastly shorter.
- In May 2023 our original StAG 14 packet reached the front of the queue for processing. We received a letter from Germany noting the subsequent creation of StAG 5 and providing guidance if we chose to switch to it. We filled out the new forms to send in, relying on the documentation from the original StAG 14 submission for the rest of the evidence.
- In September 2023 we received a letter describing several mistakes we'd made with details of how to correct them, and one last bit of evidence needed. We submitted a response within a week.
- In December 2023 we received notice that the Declaration had been accepted. My spouse and our children were now dual citizens of Germany and of the United States. It was effective as of the date the declaration was made, in June 2023 when the StAG 5 forms arrived in Germany.
- We made appoitments in February 2024 for each of them to apply for their German passports, their Reisepässe.

If you are in a similar circumstance or a descendant, born to a German mother prior to 1975, the StAG 5 process is straightforward and can be done on your own. The cost is minimal, the application is free and obtaining needed documentation will generally cost in the tens to about a hundred Euros.
Getting Help
There are several available avenues for help:
- Reddit's /r/GermanCitizenship subreddit is amazingly helpful in advice and instructions. It unfortunately didn't exist when we started this process, and I only discovered it after we'd completed the entire thing. If I'd found it earlier it probably would have avoided the mistakes we had to correct in September 2023.
- It is absolutely possible to obtain documents from Germany on your own, and I wrote two blog posts about our experiences in doing so: #1 and #2.
- There are professional genealogists based in Germany active on /r/GermanCitizenship and available for hire, who can help obtain documents.
- One can hire a legal firm, though I won't link to any because I think that is a poor use of money. Legal firms won't help you gather the documentation you need, they will at most hire a genealogist on your behalf and then substantially mark up the fee. Hiring a lawyer is the most expensive way imaginable to fill out the StAG 5 form.