Concepts – Undocumented Adoptions vs Untested Y Lines

So you took the Y-line test and you don’t match the surnames you expected to match and now you’re worried. Is there maybe an “oops” in your lineage?

One of two things has happened. Either your line has simply not tested or you have an undocumented adoption in your line.

An undocumented adoption is any “adoption” at any time in history that is not documented – so if you didn’t know about it, it’s an undocumented adoption. Often, these events in genetic genealogy are referred to as NPEs, Non-Paternal Events, but I prefer undocumented adoptions.

Yes, there are myriad ways for this to happen, and I mean besides the obvious infidelity situation, but right now, you only care about figuring out IF you have an undocumented adoption, not how it happened.

How can you tell if your line is one that simply hasn’t been tested of if there is an undocumented adoption in your line? Sometimes you can’t, you’ll simply have to wait until more people of your surname test. Of course, you can always recruit people through the Rootsweb and Genforum lists and boards and social media.

Most of the time this is a process of elimination. If you can’t find anything to suggest that you have an undocumented adoption, then your line is simply probably untested, especially if it’s not a common surname or your ancestors had few male children.

However, there are often clues lurking relative to undocumented adoptions.

Scenario 1 – Right Family, Non-Matching DNA

If you are part of DNA surname project and there are other people who have tested, that you don’t match, that claim the same ancestor as you do – you might have an undocumented adoption on your hands.

In this case, someone’s genealogy is wrong, yours or theirs. By wrong, that doesn’t mean you made a mistake. You (or they) may have tracked the line back to the right ancestor, but instead of being the child of a son of John Doe, for example, your ancestor was the child of the daughter of John Doe, who wasn’t married at the time and had a child by a Smith, but gave the child her surname, Doe.


So right Doe family, wrong child giving birth. There are also other family situations that are discovered utilizing Y DNA testing, like a child simply using the step-father’s name. In this case, finding more descendants to test, especially through other sons will help resolve the paternity question. Given the scenario above, we really don’t know whether the green or red DNA is the Y DNA of John Doe. We need the DNA of another son to resolve the question.

Scenario 2 – Accurate Genealogy, Undocumented Adoption

If you are part of a DNA surname project and two other people who descend from two separate sons of the same ancestor you claim, both having good solid genealogy back to that ancestor – you do have an undocumented adoption on your hands. This situation pretty much removes any doubt about your ancestral line if you are Steve, below.


Assuming their genealogy is correct (and yes, the genealogy could be wrong), theirs (the green) is the paternal line from that ancestor, so you need to start looking at situations that might lend themselves to your ancestor having that name but not sharing that paternal genetic line.

The break in the ancestral line can have occurred anyplace between John Doe and son Steve and the tester, Steve V.  You might want to test males descended from men between Steve Doe and Steve Doe V.  Word of warning here – if you don’t want to know the answer, don’t test.  The break could be between you and your father or your father and grandfather.  Sometimes, these possibilities are just too close for comfort.

At this point, I would turn to autosomal testing to see if any of the people in the surname project match you autosomally. That may tell you if you are actually descended from this line at all – perhaps through a female child as described above. With autosomal testing, especially of distant relatives, you can prove a positive, that you are related, but you can’t really prove a negative, that you aren’t related.

If you’re testing second cousins or closer, you can prove a negative.  If you don’t match your full second cousins, there is a problem – and it’s not the genealogy.

Scenario 3 – Matching a Group of Men with a Particular Surname

If you match a significant number of men with other surnames, with one surname in particular being closely matched and quite prevalent, it’s a large hint. For example, let’s say you have 6 matches at your highest marker level, and 5 of them are Miller men descended from the same ancestor. Chances are very good that you are of Miller descent too.

Again, I’d turn to autosomal testing at this point to see how closely you are related to your closest matching Y DNA Millers or others descended from this same ancestral line.


Scenario 4 – Your Line is Untested

If your surname is something quite unusual, like Ferverda for example, and you don’t fit the situations described above, then it’s likely that your line simply hasn’t tested yet. In this case, the grandfather of our tester was the immigrant from the Netherlands, and Ferverda, both there and in the US, is a very unusual name.


Of course, your line having not tested can happen with common surnames too.

Utilizing Y Search

Update: Please note that YSearch was obsoleted due to GDPR. It has been replaced by

Check periodically to see if others of your surname took the Y chromosome test elsewhere and just got around to entering the results into YSearch, even though the other testers (Ancestry, Sorenson) have been defunct for some time now relative to Y DNA.


You can also search at YSearch by surname. You don’t have any way to view results by surname, outside of projects, at Family Tree DNA, so the only way to discover that someone who claims your paternal line and doesn’t match you is to search by surname at YSearch and hope they have included a tree.


In this example, one person with the Estes surname has results at YSearch, but 40 have Estes in their tree, just not as their patrilineal surname.


Keep in mind that depending on how far back in time an undocumented adoption occurred, you may find matches to people with that same surname who descend from your common biological ancestor, but you may still not share the original ancestor. In the example above, the Doe men red all match each other, because their unknown Smith ancestor is the same, but they don’t match the descendant of John Doe through son James.

A non-match to men of your same surname isn’t a cause for panic, but it is time to do some additional digging to see if you can discover why.

Happy ancestor hunting!



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33 thoughts on “Concepts – Undocumented Adoptions vs Untested Y Lines

  1. I am very glad to see this article. I am working on three families with this problem: Brown out of North Carolina, earliest ancestor born 1790-1800; Clements/Clemmons, earliest ancestor born 1770s; Hudson from Darlington County, South Carolina, matches Marshall. The biggest problem at this point is finding additional testers.

    • I have Brown’s from NC and I have tested several of us by Family Finder and Ancestry DNA. Also 23andMe but I doubt that will help much. Abraham Brown b.1756 Rowen Co. NC.

      • My Brown has a neighbor, William Brown, a possible brother, who was married in Rowan County, NC in 1820. If you have someone who can take a yDNA test–or has a Family Finder that I could add a Y-test to, it would tell me whether the Oops! happened in NC or TN.

  2. We had an unrecorded adoption (not adopted) but the mother gave her last two children the surname of the deceased husband. I was very lucky to stumble onto court records from 1828 for a paternity suit and have dozens of matches with descendants of this non-adoptive father’s siblings. There are several YDNA testers that match us and some of them had the same sort of problem. Apparently it wasn’t uncommon not to marry the mother of your children or to leave them.
    I love your posts. They are so helpful! Thanks for all you do.

  3. Roberta, what is the best parameters to use in Y-search to find genetic matches, regardless of last name within a time depth of 300-400 years?
    It asks how many markers to consider and then maximum genetic distance. Should I limit by haplogroup subclades, or am I just shaving off potential matches that tested fewer markers?

    I’m somewhat satisfied I’ve found most matches back to the early 1700’s, but I’m at the point in the mid-1600’s where I need to start finding deeper matches.

  4. A few words of caution about matching a bunch of men with one non-target surname, e.g., the five “Millers” —

    In the Brown DNA Study, we see this phenomenon once or twice almost every month. I believe it often comes about simply because some particular “Miller” researcher has been very active in recruiting test participants from his or her own extended family. The large numbers of matches (five or six or whatever) may have no special significance, because we are seldom dealing with something like a random sample.

    Therefore, I tell project members not to get enthusiastic about finding a relationship to a long list of “Millers” unless at least one of the following conditions is met:

    1. One or more of the “Miller” matches is at 37/37 or better.

    2. Your family has some kind of oral legend or other tradition of a relationship to the “Millers.” For example, “My great-grandfather said he thought we used to be Millers.”

    3. You find a “Miller” family next door (or very close) to your Brown ancestors on an old census or tax list.

    4. You have other non-DNA evidence of a relationship to the “Millers.” For example, one of your ancestors was named “Miller Brown.”

    Otherwise, my experience indicates that if you spend a lot of time researching the “Millers” just because you find a lot of them on your match lists, you’ll usually be headed up a blind alley.

    • I agree Jim, I’ve often seen people jump to conclusions too quickly based only on a certain surname occurring more frequently among their matches. This could be from 1) more active recruitment, 2) a common surname where people are just more likely to use DNA because the name is hard to sort out in documents, 3) a project with funds to sponsor tests making growth faster, 4) projects that started longer ago and have had more time to grow, and 5) projects for surnames that are more expected to have multiple origins, 6) projects that share more than one of these characteristics …

      • I have experienced dealing with Y-matches that are predominantly “Brown” (for sake of argument), with a single “Clemons” at the top of the match list. Hunting for matches to the “Browns” was futile (although in the “Brown” surname project, the two Clemons were well matched to a particular Brown cluster). A researcher for the relevant haplogroup project was able to determine that the Browns actually broke off from the Clemons instead of what the Clemons matches anticipated branching off from the Browns. So, in actuality, the time and research has been proven we should focus on the Clemons. We’re getting closer to figuring out common Clemons ancestors in the Emerald Isle as a result of being a bit open-minded…

  5. Another great article, Roberta. However, I might add…

    Another problem is the current state of the art of the testing. The majority of peoples Y-DNA matches are in the pre-geneology time frame – over a thousand years ago. While most peoples autosomal matches are in the time frame of the last few hundred years. The two time frames rarely overlap, if at all. Mostly, they are far apart. But advances in the state of the art of the testing is slowly narrowing that gap. I think in another ten years or so, using Y-DNA in conjunction with autosomal DNA will be much more helpful in trying to solve these kinds of thorny cases.

  6. I have tested at 111 markers thro FTDNA. I have close matches at 67 markers with several well documented Bryans who trace their line back to Morgan (b ca 1671, d. 1763, Rowan Co, NC) and Martha Strode ( 1697, d. 1762, Rowan Co, NC) Bryan. Our DNA places these matches solidly in Irish Type 3, with kinship to O’Briens going back to Brian Boru. Another bunch of Bryans, also meticulously documented back to Morgan and Martha Strode Bryan, have very close matches. Their line to Motgan and Martha is indisputable. The first group of Bryans (my group) descend from Morgan and Martha Bryan’s son Morgan Bryan, Jr. (b. ca 1725-1727, d. ca 1804 KY) and wife Mary Forbis. The second group of Bryans descend from Morgan Bryan Jr’s younger brother William Bryan, b. 1734, d. 1780, Bryan’s Station, KY), married to Mary Boone (b. 1736, PA), sister of Daniel Boone. The DNA of Morgan Jr’s descendants does not come close to matching DNA of William’s descendants. It is our belief that William and perhaps other brothers may have been adopted. Of the 7 brothers (Joseph, Sam, Morgan Jr, John, William, James, Thomas), we have many DNA samples going back to Morgan, Jr and William, one 67 marker test of a direct descendant of James (DNA does not match either Morgan Jr or William, but one test is insufficient), No known Y-DNA tests by descendants of the other brothers are available.

  7. Thanks Roberta for this post! We just received my husband’s Ydna results back and are confused as how to read them. A little background- his great great grandfather was born about 8 years after gg grandmother’s husband died, so we have always been sure that there was NPE involved. His gg grandfather even used his rumored father’s name on one document, then reverted back to his mother’s surname for the remainder of his life.

    His Y results show 3 matches at a distance of 0, one of the matches share the same gggg great grandparents with his rumored line. The other two matches share a completely different surname.

    He has a total of 37 matches, spanning genetic distances from 0 to 4. Both surnames repeat throughout, with a third surname showing up in distance 1. He matches none of the people in his given surname project, as expected. Y search shows more matches to the rumored/suspected father. So, should we consider that the rumored line is correct since he has more than one match with that surname? Or should we consider the other surnames in the 0 distance matches?

    We did the 37 marker test just to get things started. Would doing more markers be more helpful?

    hope this makes sense

  8. Woman gives birth under the married couple’s name. They take the baby home. Or, ob-gyn impregnates his willing and married patient. Unsuspecting husband and complicit wife take the baby home.

  9. Given my y-DNA doesn’t test to Smith, but Diehl and I evidently am the only one trying to trace back to my most distant Smith on my paper trail. My at-DNA turns up a second cousin in the Deal (current spelling) line. So we would have the same great grandparents? My NAD also has an entry for being connected to the Deal spouse, a Bisanar. And my dear Mom, long passed away, made an off-hand reference to my Grandfather being a foundling, and then changing the subject. So it is likely that instead of a Smith, he was a Deal/Bisaner. His Mother and Father were married in Nov 1883, he was born Nov 1884, which fits into the Deal/Bisanar timeline. How can I narrow down and be relatively sure (pun not intended, but I like it) that this Deal was the probable sire of my Grandfather?

  10. What would be the assumed reason when you have lots of matches 0 at 12 even though you tested to 37 and a lot of those matches have tested to 111 but the only matches that have the same surname are the ones where small family groups all related to each other have tested and their matches also show no further back than 12 also the people matching at 12 have no histories further back than great grandfather and the last place of residence for the majority the Greek Islands then a larger group to Ireland, then a scattering through America’s and close places to that continent ?

    • Well nobody seems to be able to solve this problem, surely it is not a unique situation, did all these men only have christian names and then pull their surnames out of a hat or from a lotto pool when they entered the country they ended up in, or has their DNA not altered since they were Neanderthals ?

  11. How can I track down my great grandfathers parentage. I have many close matches two to three generations to him.
    However oral rumor has his mother and an unnamed father of a certain family. A family bible lists his parents as her father and a woman of that surname as his mother. His death certificate lists her father and an unknown mother
    I have many matches with the certain family.How do I track down his parents?

  12. Very helpful post, Roberta. I confirmed an undocumented adoption for my paternal grandfather using both Y and autosomal DNA. In my initial research days, there were hundreds of Y matches, but with no clear common surname. Very frustrating. Eventually, I sought out men based on scant family lore, and identified the correct surname.

    That was a few years ago, and I’ve since traced my paternal line back to my 5th great-grandfather. I’m now eager to continue tracing the surname (hopefully back across the pond), but the expense of testing still demands judicious testing (as opposed to an open free for all of everyone of a same surname, which would have the added benefit of creating robust databases).

  13. Of course Ysearch dot org would actually have to be working to utilize it. Haven’t been able to get into it for at least two months. When I contacted support at FtDNA they essentially said they could care less about supporting it, because FtDNA was better and more useful.

  14. In my husband’s line it appears that his 3X great grandfather, Ptholomeus Delfers, took his wife’s last name in order to inherit her father’s property. as he had no male heirs. Most of my husband’s Y-DNA matches are to individuals named Folkman(n) so perhaps we have a combination of assuming the wife’s name and NPE.

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