This project hopes to establish the relationships among people with the surname Birnbach and its variants. While a surname itself may give us incomplete or misleading or, at best, only general information about the origin of a family, DNA-testing can give us concrete evidence for identifying and separating family lines. Y-chromosome DNA testing is especially helpful because the male Y-chromosome is handed down, father to son, unchanged through the generations, except for rare mutations which, in themselves, can be helpful indicators of branching.