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Grandparent DNA Testing: What You Need to Know

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If you are planning to perform a grandparent DNA test at PaternityUSA, many questions may be running through your mind. They often result from a lack of knowledge about the subject. Therefore, understanding this concept further will help answer questions related to this issue. Fortunately, you can learn a lot from this article. So read on as we uncover the facts about this particular paternity test.

When should I take a paternity test for my grandparents?

Always remember that paternity testing of the child in question and the alleged father is best. However, if the father is unable to be present for the test, paternity testing by grandparents is the best option.

What samples will be collected?

Grandparent test kits work well with oral swabs. A DNA sample is taken from your cheek using a cotton swab. However, some tests are done using a blood sample.

Types of grandparent DNA testing

These tests fall into two main categories.

Double grandparent DNA test

As the name suggests, both grandmother and grandfather participate in this test. Samples of alleged grandchildren are also modified and comparisons made. It is considered the best grandparent DNA test because it increases the likelihood that strong and correct conclusions will be drawn from the results. Because the samples are from both grandparents, scientists will be able to use more relevant DNA markers. The result is a conclusive result that easily proves whether there is a biological relationship between the parties involved.

Single Grandparent DNA Test

This test involves an alleged grandfather or grandmother. It’s not as good as the two-grandparent test, but it may be your only option. After all, one of the grandparents may not be able to undergo a paternity test. If so, be sure to include your birth mother’s DNA sample as well. Having all three samples available increases the likelihood of a conclusive result.

What percentage of your DNA comes from your grandparents?

For DNA tests between grandparents and grandchildren, the average percentage of grandparent and grandchild DNA is usually 25%. That’s because grandchildren receive 25% of their genes from all of their grandparents. This explains why they produce children that resemble their parents. It also explains why grandparent DNA is an option when proving parentage.

How accurate is a grandparent DNA test?

If performed correctly, grandparent testing can be surprisingly accurate. In most cases, especially when both grandparents are available, accuracy is typically up to 99%. This may not be the case if you only deal with grandparents, but experts always come up with the right results depending on the situation.


I hope you learned a lot about grandparent DNA testing. In addition to testing involving grandparents and grandchildren, here are the facts we now know. These include the accuracy of the paternity test and the samples that may be required. You’ll also know when it’s the best option and the different types you have at your disposal.