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  • How accurate is a grandparent DNA test compared to a paternity test?
    A grandparent DNA test is as accurate as a paternity test, although the conclusiveness of results can vary more. For example, the probability of a relationship between a father and child is almost always 99.9% or higher, but for a single-grandparent test (where only one paternal grandparent is tested instead of both paternal grandparents), the probability of relationship might be 92%— which is nevertheless still considered a conclusive result. To strengthen the conclusiveness of test results, we recommend that both paternal grandparents test (if possible) and that the child’s mother participate in testing, as well. When both paternal grandparents and the mother participate in testing, probability of paternity is nearly always 99.9% or higher.
  • Can we test using just one grandparent?
    You can do this grandparent DNA test using samples from just one paternal grandparent and the child; however, the chances of obtaining conclusive results are reduced. If possible, we always recommend including the mother’s DNA in both single-grandparent and grandparentage (both paternal grandparents) DNA tests. Ideally, both paternal grandparents would test, along with the child and the mother.
  • Can a grandparent DNA test be done without the mother?
    Yes, a grandparent test can be done without the mother, although we highly recommend that the mother be included as well. Her participation helps the analysts to more clearly determine which of the child’s DNA comes from the father’s side and which comes from the mother and it can also help to strengthen the probability of relationship percentage.
  • Can a grandparent DNA test be used for legal reasons?
    Yes; a grandparent DNA test can be used for legal reasons as long as a chain-of-custody procedure has been set up and followed: The test is ordered directly from DDC DDC schedules a DNA-collection appointment for test participants at a convenient facility near them Test participants provide proof of identity at the appointment and DNA-collection is witnessed The facility signs paperwork and returns samples to the lab for testing Results from a legal grandparent test are court-admissible and can be used for legal reasons such as Social Security, inheritance rights, custody, and more. Results for an at-home grandparent DNA test cannot be used legally.
  • Does the mother need to consent to a grandparent DNA test?
    Whether the test is an at-home or a legal one, the responsibility is on the tested parties to ensure all parties and/or legal guardians agree to testing.
  • How do I understand results for a grandparent DNA test?
    Understanding results for a grandparent DNA test is a little tricky, since there can never be a straight “yes or no” answer in relationship testing. Calculations for relationships such as grandparent, avuncular (aunt/uncle), and siblings all involve statistics, and a probability of relationship is given as a percentage in the report: 90% or higher: the relationship is supported by DNA testing 9% – 89%: inconclusive result, and additional parties need to be tested Below 9%: the relationship is not supported by DNA testing If a probability of relationship (PRI) of 92% is given for a grandparent test, the result could be understood as: “There is a 92% probability that the persons tested share a grandparent/grandchild relationship.”
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