In Adams story he tells us that he felt Circen in utero. And we are also given the impression that he attended his son's birth (ref when he told Morganna that he loved her).
If he had happened to have another child with another woman he would have had the "conection" to that women (remember that connection happens when a child is conceived).
I do think that JB is OLD, and that he is either a Druid or half Fae, but I am don't think he is Adams. I was thinking maybe one of the other Fae who seem to have "disapeared". No one knows where they went.