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How Grandparent DNA Testing Helps in Determining Paternity?


Paternity can be established through the use of a grandparents and grandchild DNA test, especially when the father is unavailable or deceased. The DNA profile of the grandparents contains essential components found in the DNA of both the grandchild and the alleged father. This test is most accurate when both grandparents are available for testing.

Can I Test One Grandparent, or Should I Test Both?

It’s feasible to conduct a paternity test using grandparent DNA, either from one or both grandparents. However, relying on just one grandparent may yield inconclusive results, which many companies do not offer. While it is scientifically acceptable to test only one grandparent, reputable labs suggest testing both. It’s advisable, when performing a grandfather or grandmother DNA test, to also include the mother’s sample. While some DNA labs might not provide this option anymore, it can still be pursued if it’s the only available choice. Including the mother’s sample contributes to a more accurate outcome. It’s important to approach the results with an open mind, as there’s a chance of a false negative result. This occurs when the child has inherited DNA from the untested grandparent of the alleged father, falsely indicating no relationship. Therefore, testing both grandparents is preferred to provide a comprehensive view.

Understanding Grandparent DNA Testing in Missing Person Cases

Each person’s DNA profile includes two values for each genetic marker, one from the mother and one from the father. The child’s genetic markers inherited from the father must match those in the grandparents’ DNA profiles. By thoroughly examining the grandparents’ DNA profiles, the lab can determine whether there’s a match with the child. The lab evaluates all possible combinations to draw conclusions. Ultimately, this approach accurately establishes whether paternity, particularly in cases of a missing father, is confirmed or excluded. Referred to as a “missing person report,” this method is invaluable in establishing paternity when the alleged father is deceased.

Grandparent DNA Testing: Y Chromosome

In cases where only the paternal grandparent is available and a male child is involved, a Y chromosome test can be conducted. This test determines if two males belong to the same male lineage. Through generations, the Y chromosome is passed from father to son. This test offers an accurate method to establish paternity when the alleged father is absent. With advancements in DNA testing technology, various options are available to address paternity inquiries.