When is a grandparents DNA test used?

This type of test is done as an alternative to a DNA paternity test when the alleged father is not available for the test. Grandparents will have genetic material in common with their grandchild/children. By testing the alleged father’s parents and comparing their DNA to that of the father’s child, we can indirectly establish paternity. It is important that you provide us with a DNA sample from the paternal grandmother and paternal grandfather in order for us to carry out this test. We cannot offer the test with a DNA sample from just 1 grandparent.

If the alleged father is available, we recommend a father to son/daughter DNA test. See our home paternity test page for information.

How accurate is a grandparents DNA test?

The results of a grandparents test are extremely accurate. This is because using the recombined DNA from both grandparents, we can extract what we refer to as a “derived profile” – this profile is the DNA profile of the untested, alleged father. Once we have this profile, we can compare it to the DNA of the grandchild to establish a biological relationship.  If the grandparents result as an inclusion, then we can say that the untested alleged father is the likely the true biological father of the child (the grandchild of the grandparents).

Grandparents DNA sample collection

Our grandparents DNA test kit will contain mouth swabs for the grandmother, grandfather and grandchild. You will find 4 swabs for every test participant as well as instructions on how to collect your samples, consent forms and a pre-addressed envelope which you can use to return your samples. Mouth swabs need to be rubbed inside the mouth and under the tongue for a few seconds in order to collect cheek cells from the lining of the mouth. For more information about sample collection, click here.

Exclusively male test participants

Related males have on big advantage when it comes to establishing whether they are truly related: this is their Y chromosome. The male Y chromosome undergoes little mutation from one generation to the next and is passed down the male line unchanged. The Y chromosome is a very strong indicator of a shared paternal lineage and if males share the same Y chromosome profile, they also definitely share a common paternal ancestor from whom they inherited that Y chromosome. This means that if you are males and want to know whether you share a common paternal line, a Y chromosome test will answer your question.


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