Help me out, I’m curious: how would adoption make quantitative genetic matching more complex? Investigative genealogy, for sure it would, but this is pure math and data sets. Not seeing the connection? Also, why are people submitting to be matched to him, as opposed to submitting into GEDMatch’s data pool overall?
Let's say for example that the Doe's father is adopted. You have his family, know who his birth parents are, but you don't know who he
is. In many places, these records are sealed especially if he might be alive. Not knowing who he is, his new name, adoptive parents etc, means you can't trace any children he's had. Imagine adding an NPE to that - so the Doe has a different father on paper, or is even adopted himself. Things get very complicated. You can't make the matches where it count for genetic genealogy if nobody is genetically who they think they are/who they are on paper.
I know of a woman who is an NPE, her mother had a one night stand whilst married. After DNA testing the woman has found her biological father's birth family, but he himself is adopted and they don't know his new name or who he is. So it's a very odd situation of the woman knowing her biological grandparents and family, and being very accepted, but neither her nor her grandparents know who her father is.
I think there's a similar situation with another Doe - a female, can't remember which one. Her father appears to have been adopted, born to a German mother and African American serviceman. They know what his birth name was but he was adopted out and without knowing who he is now, they can't trace who the Doe is.
Sounds like this Doe's tree is tangled, I hope they can figure it out.
ETA - the matching thing is just a fun thing they're doing to generate interest. They ask people to submit what their GEDmatch kit number is and then they make a post to say if you match him. It makes things more interactive and interesting if someone finds out they are connected to a Doe, even very distantly.