Can an Ancestry DNA test prove paternity?

Are you wondering whether Ancestry DNA can be used to determine paternity? Well, hold on I'm going to give the answer.


DNA is amazing at identifying close relationships so I'm going to explain how DNA might be able to be used to determine paternity.


Ancestry DNA is the largest commercially available DNA database. One of the amazing things about DNA is that it can tell you about close relationships almost exactly. So we want to look at whether or not this DNA test is going to be able to tell you about your paternity.


Now in order to do this, what you need is two people to take a test. One person doesn't know who their father is and the potential father. You'll compare these two tests together. Ancestry will do this comparison automatically.


As you receive your results, Ancestry could reveal your paternity, but there are some caveats.


To listen to Andy explain the caveats, watch his video.

Video: Can an Ancestry DNA test prove paternity? -


Can AncestryDNA results prove paternity in the legal sense?


The first caveat is actually rather easy. If you want to have a legal document to prove paternity, you need a court order to issue a ruling to obtain child support or anything like that.


From a legal standpoint, Ancestry absolutely cannot be used to validate paternity. For one thing, Ancestry's terms of service prohibit the use of their results in this fashion.


Secondly, for legal documentation, you need a chain of custody. In other words, there needs to be a court-approved method where:

  • Somebody sees you spit into this bottle.

  • Then that bottle is taken to Ancestry with a courier or with some other method where they know that that bottle is still your spit.

  • Then that bottle is processed under review making sure that they know that is your saliva and not a substitute.

  • Finally, the results must be reviewed to ensure that the results that come out belong to the original person that spat.


When you take a DNA test, Ancestry sends you a box. Now you told them your name but your name could be anything. In fact, I took a DNA test for Phil Garnett, who is not a real person, which you can watch here. The results are comically funny.


In short, Ancestry has no definite way to tell that a sample actually came from you. It might have come from your brother, sister, or your dog. There is no chain of custody.


From a legal standpoint, you are not going to be able to use Ancestry DNA for determining paternity.


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Can your DNA test results prove genealogical paternity?


Let's just worry about a genealogical standpoint. Does your DNA show who your father?


If you two people take a DNA test, the person who doesn't know who their father is and the suspected father, because of such a close relationship, in almost all instances Ancestry DNA will be able to identify whether the second person is the father of the first or not.


It's really that simple.


You're either that closely rated that you have to be the father or you're distant enough that you're not the father.


You should always be aware of where this falls apart is with identical twins. Identical twins share the exact DNA. As far as the commercial DNA tests are looking at ancestral DNA is not going to be able to tell you whether Twin A or Twin B is the father.


When testing with Ancestry DNA, the DNA of identical twins is exactly the same, and as such Ancestry will identify the test as "Self." (Well, after a series of emails ensuring that the test is for a different person- see the video about Phil that I mentioned earlier.)


Short Answer:


Can use Ancestry DNA to legally determine paternity? No.

Can use Ancestry DNA to genealogically determine paternity? Most of the time.



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