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Grandparent Paternity Testing
Updated on February 7, 2024
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DNA Testing
Grandparent Paternity Testing

A grandparent DNA test can help establish paternity or maternity if the father or mother is unavailable. It can also verify the biological relationship between a grandchild and their grandparent.

Some DNA tests (like maternity or paternity tests) can help confirm whether or not you’re biologically related to someone. When there is a match, it suggests that two people may be relatives.

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Why Take a Grandparent DNA Test?

There are several reasons why you might consider a grandparent test. For instance, you may want to:

  • Confirm paternity when the alleged father isn’t available for testing
  • Establish maternity when the alleged mother isn’t available for testing
  • Gain legal grandparent rights (e.g., custody, inheritance, and visitation)
  • Make sure that a child is your biological grandchild for peace of mind

Grandparents, grandchildren, parents, or the court can initiate the test.

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How A Grandparent Test Works

DNA samples must be taken from the child, the child’s mother, and one or both grandparents from the father’s side.

This is usually via cheek swabs or blood samples, depending on the testing company or laboratory.

Testing both grandparents allows a DNA company to reconstruct the father or mother’s DNA.

They can compare it with the child’s DNA to establish paternity or maternity more accurately. The parents of the alleged father will share a good amount of DNA with the child if it turns out the child is his.

The duo grandparentage test is the best way to reconstruct the alleged mother or father’s DNA and compare it with the child’s. It can also predict how likely a child is related to their maternal or paternal grandparent.

Note that if only one grandparent is tested, it can lead to inconclusive results. Since it’s less accurate, it may not be enough to establish legal paternity, maternity, or grandparent rights. 

Grandparent DNA testing can be done in medical facilities with the supervision of professionals. But you can also take a grandparent test at home.

Collecting DNA Samples for Grandparent Testing

A cheek swab sample is usually more common. A medical technologist will gently scrape the insides of your checks with a cotton swab to collect a buccal sample.

Besides a buccal swab, some DNA testing companies require blood samples from the parties involved.

Is Grandparent Testing Accurate?

Yes, if the samples are collected and tested properly. A child will always share around 25% of their DNA with their biological grandparents and around 50% with their biological parents.

This means that if the paternal grandparents and the child share this much DNA, it's highly likely that the alleged father is the child's biological father.

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Source: 123rf

Can Grandparent Testing Be Done with Just One Grandparent?

Technically, yes, but both grandparents are usually encouraged to take the test to achieve more conclusive results. Courts may rule out results from just one grandparent.

Can You Get A Legal Grandparent DNA Test?

Yes. You can get grandparent testing to support legal cases. 

However, this is only possible if the samples are collected and processed in court-approved facilities. Examples include hospitals, health departments, and medical offices.

A court can accept your grandparent test results if a qualified professional:

  • Monitored the end-to-end DNA collection process 
  • Verified the identity of the people whose names are in the report
  • Witnessed the handling of cheek swabs
  • Completed the paperwork
  • Mailed the samples to the lab for analysis

Talk to a lawyer if you want a legal grandparent test. The child’s legal guardian may refuse testing. If this happens, you can ask the court to order the test.1

Are At-Home Grandparent Tests Court Admissible?

Most at-home grandparent DNA tests can’t be used in court, even if they provide the same results as a legal test. They don’t meet the criteria necessary for legal DNA testing. An at-home DNA test kit is also easy to mess up and tamper with, so courts prefer more controlled labs.

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Source: Unsplash

Benefits of Legal Grandparent Testing

Courts may grant legal rights to grandparents if they can establish a biological relationship with their grandchild.2 Listed below are some of them:

1. Visitation rights

If your daughter (the child’s mother), son (the child’s father), or legal guardian prevents you from seeing your grandchild, you can appeal for visitation rights.

All you need to do is take a legal DNA test that proves your genetic family relationship with the child.1 

Laws vary across U.S. states, and courts tend to side with the parent. But there are situations when you can be granted the right to be a part of your grandchild’s life.

Establishing a genetic link between you and your grandchild is the first step in achieving this goal.

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2. Inheritance concerns

Grandparents who want to plan their estate and ensure their grandchild’s inheritance may want to prove their grandparent status.

If a child wants to claim inheritance based on their genetic relationship with the alleged mother, father, or grandparent, a DNA test may also confirm their rights to the estate.

For example, if a father dies without a will and has a child out of wedlock, a DNA test can determine whether or not they can claim inheritance.

The Wills, Trusts, and Claims section of the Inheritance Act of 1975 allows the use of DNA results to resolve inheritance disputes.3 

A person can choose who to leave their possessions to. But if they die intestate (without a will) and the probate court has to decide on inheritance, they will base their decision on legally established ties.

If you want the right to inherit the property of someone you believe is a biological grandparent, you may need DNA testing to prove it in court.

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3. Child custody

If, for some reason, the alleged father is not available and grandparents want to obtain child custody legally (or other legal reasons), a grandparent DNA test may also help their case.

Should You Get A DNA Grandparent Test?

You can take a grandparent test if you want to confirm the maternity or paternity of a child and the child’s mother or father isn’t available for testing.

It can be useful if the mother or father is missing or deceased, and their parentage has not been previously established.

Grandparents should also consider this DNA test if they want to gain legal rights or simply want reassurance that they are biologically related.

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Updated on February 7, 2024
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3 sources cited
Updated on February 7, 2024
  1. The Rights of Grandparents.” American Bar Association.
  2. Grandparents’ rights and DNA testing.” Dinnebier & Demmerle.
  3. DNA Testing in Wills, Inheritance, and Estate Disputes.” DNA Legal.
Dr. Rizza Mira
Dr. Rizza Mira
Medical Reviewer
Dr. Rizza Mira is a medical doctor and a general practitioner who specializes in pediatrics, nutrition, dietetics, and public health.

As a pediatrician, she is dedicated to the general health and well-being of children and expecting parents. She believes that good nutrition, a healthy lifestyle, and prevention of illness are key to ensuring the health of children and their families.

When she’s not in the hospital, Rizza advocates and mobilizes causes like breastfeeding, vaccination drives, and initiatives to prevent illness in the community.
Cristine Santander
Cristine Santander
Content Contributor
Cristine Santander is a content writer for KnowYourDNA. She has a B.S. in Psychology and enjoys writing about health and wellness.
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