I completed a Family Tree DNA test for Y-DNA. My results show I have only six matches. I have viewed the available trees of 4 of the 6 trees, the others are private and unwilling to cooperate. I cannot find any matches but unsure if the Y-DNA is giving me a false positive if that is possible. If I were to compare X-DNA and Y-DNA, would that give me a more accurate rendering of DNA matches? Actually. I am not sure such a comparison is possible.

I am a newbie at using DNA as a resource for finding my ancestral surname family. I am trying to find Farrell family beyond my great grandfather. Any suggestions or corrections to my interpretation of my Y-DNA results.

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    – Jan Murphy
    Commented Sep 19, 2016 at 15:36
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    Comparing X-DNA and Y-DNA is not meaningful. Can you explain why you think the Y-DNA matches are a false positive? How close are the matches? What level of Y testing have you done (how many markers). If you can illustrate the question with some real (anonymised data) that would be helpful.
    – user104
    Commented Sep 19, 2016 at 15:45

1 Answer 1


It is extremely rare for Y-DNA analysis to give a false positive. However, the people you match to may connect 10, 20, or 30 generations back which is likely not genealogically relevant since you won't find records that far back to determine who the common ancestor is.

If you've only gone back to your great-grandfather, you should take an autosomal (or Family Finder) test, which will find probable relatives on all your sides out to about 5th or 6th cousins. You can see if any of them have your Farrell surname among their ancestors or in their tree which may be on any of their lines, not just their male line which the Y-DNA test determines.

The X chromosome will not help you much. You might think you can eliminate people with an X match because they won't be on your father's side, but you never know because people can be related to you in multiple ways, and one of those other ways might be through your father's side.

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