My paternal grandfather's name was not permitted to be on the birth register of my father. How does one find Unknown Unknown? through time and place? Thru DNA tests? through a GEDmatch? I think I've tried them all.
My autosomal DNA TEST shows a definite Jewish (Ashkenazi) dna from Lithuania now called Belarus. This person was very likely in Karlsruhe or Frankfurt in March 1907. My grandmother Anna's family seems not to have been rich enough to travel long distances as a general rule. An inference I made after meeting the three Bermans two years ago is that my and my son's keen interests in the arts comes from that Jewish family line. Other than that I don't know anything about him.
I am female and my father had no living male relatives except for his father. I had two sons and both had the same test taken.
As for a GEDmatch, I'm at a point where I've run it and received results. Now I must write people short letters to get further information.