Birkenstein is a civil parish of Hoppegarten . European refugees to the United States sometimes used the names of their European homes as surnames. Almost all ' Birkensteins ', for example, reside in the United States
http://forebears.co.uk/surnames/beirkenstein
...the point being that people named ' Birkenstein ' are not necessarily Jewish- so you'd be wrong to assume that they were. ' Stein ' means ' stone ' in German, of course, and Frankenstein wasn't Jewish - as far as I know.
Interestingly, the prefix ' Paleo- ' denotes ' ancient ', so the compound word ' Palestine ' takes the meaning of ' ancient stone '. Some morons claim it never existed.