Finding the father

Hello,

DNA matches suggest that it is very likely that my grandfather's biological father was not the person named on his birth certificate who was married to the mother at the time of the birth (and had been for at least 10 years previously, though they appear to have become estranged in the decade following the birth of my grandfather, who was their last child).

There are a number of close matches with people descended from a family who were living in the right area (Islington/north London) at the time of conception. My question is how to zero in on the biological father. That family had three or four males...

Any advice gratefully received.
H

 

They were brothers...

 

Clarification? By "DNA matches suggest", you mean that you have no DNA matches with any of his siblings, or parents families? Are you classifying (usually by using the Group feature) your DNA cousins into which of your four grandparents they are related to?? If so, you should be able to identify the closest cousin who doesn't fit any of the other three. Then check this cousins "Shared Matches" to see if they can be allocated. If not this group of cousins are probably related to your real grandfather.