An Avuncular Test determines the likelihood that one person is related to someone else as a biological aunt or uncle.  The term, Avuncular in this context means resembling an uncle.  Avuncular Tests are used to determine paternity; to check whether or not the biological brother of a tested person is the biological father of the child.  This test is of great use in cases where the biological father of a child is deceased or unwilling to participate in a Paternity Test.

Where can the Avuncular Testing be used?

Avuncular Testing can be used extensively in cases where paternity of a child is needed to established to:

  1. Acquire the custody
  2. Obtain social security benefits
  3. Settle an inheritance claim

Provide a proof of a biological relationship between an immigration applicant and their U.S. citizen sponsor.

How does it work?

A child obtains half of his/her genes from the biological mother and the other half from the biological father.  These are called as maternal genes and paternal genes respectively.  A father shares half of his genes with his full sibling.  This means that the child shares half of his genes (earlier called as paternal genes) with the full sibling of the biological father.


The first step is comparing the number of genetic markers between DNA of the child to that of the alleged uncle or aunt.  Then by the statistical strength of these matches, we calculate the likeness of the so-called uncle or aunt being the biological relative of the child.


If the result of an Avuncular Testing reports a probability of 99% or greater for a child, and an uncle or aunt exists, then such a result is considered as conclusive.  An applicant opting for Avuncular Testing should keep in mind that with this test, it may not be possible to get a conclusive result unless the mother is included.

Inconclusiveness and the requirement of the mother

Sometimes it is hard to achieve a conclusive result.  Even the biological father of the child and his sibling share the same parents, the full sibling is not at all genetically equivalent to the child’s father.  The full sibling might have inherited a few of genes that the child’s father might have not.  Our team at Brooklyn DNA Testing have found that if genetic markers of an alleged father’s full sibling are compared to that of the child, we care only able to find half of his genes.  Hence, in an Avuncular Test, we recommend that the mother of the child should be tested as well.  If the mother of a child is tested, then maternally inherited genes can be separated and the probability space gets reduced to paternal genetic markers only. Hence, we do not recommend performing Avuncular Testing without the presence of the mother of a child as there is a substantial possibility of the test resulting in as inconclusive.

The most conclusive Avuncular Testing

If both the persons that are being tested are males i.e. a male child and the alleged paternal uncle, Y-STR Tests can be performed.  Y-STR stands for Y-chromosome typing, and such cases are completed.  As you might now, Y-chromosome is a type of DNA structure that is found exclusively in males and transferred from the father to each of his sons.  Due to this inheritance, full siblings of an alleged father inherit the same Y-chromosome.  So if the Y-chromosomes of a child and his alleged uncle does not match, then it can be concluded that the alleged father is not the biological father of the child.  But if the chromosomes match, then the likeness of the alleged father being the biological father will be more than 99%.  This type of Avuncular Testing cannot be used to test uncle-niece, aunt-niece & aunt-nephew relationships as females don’t have Y-chromosomes.

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