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Sibling DNA Test

To determine a biological sibling or half-sibling relationship.

Is He my Brother or my Half-Brother?

Do you want to know if you and your sibling share the same father? Not sure if your children are from the same man? Or do you want to confirm a possible relationship discovered through ancestry testing? There are many reasons for doing a DNA siblingship test and DDC offers the latest technology and accurate testing to resolve questions about biological-sibling relationships.

Not sure if a sibling test is right for you? Contact our experts today for a free consultation.

The DDC Promise

Results in 5 Business Days

Once all samples arrive at the lab.

PhD-Reviewed Results

Our in-house team ensures accuracy.

Team Support

We keep you informed every step of the way.

When set up as a legal case, results from a sibling DNA test can be used for inheritance benefits, proof of relationship for immigration, and more.

Reasons to get a Sibling DNA Test

The most common reason for taking a sibling DNA test is to confirm the truth about whether you and your sibling share the same father. Other reasons to take the test are:

  • Medical history
  • Social Security benefits
  • Inheritance claims
  • Immigration cases
  • Insurance claims

Results are completely confidential, and your private genetic information is never shared with or sold to outside parties. See our privacy policy here.

Testing Options for Sibling DNA Testing

There are two main options for doing a sibling DNA test: legal or for personal knowledge.

Legal: Legal test results for siblings can be submitted to court as legal proof of a biological relationship. DDC coordinates DNA-sample collection at an approved location near you. The professional collector then compiles all identification, completes paperwork for the test, and sends the package to DDC for testing.

Personal Knowledge: If you need the sibling-test results solely for peace of mind and not for legal reasons, you have the option to collect your samples at home with the sibling DNA test kit and then send them to DDC for testing. Keep in mind results are not court admissible.

TIP: If you think you may need results for court in the future, we suggest you do a legal test first, so you only have to test once.

To order a Sibling DNA Test, call

More about this Test

Q: Can sibling DNA test results be used for legal reasons?

A: Yes, sibling DNA test results can be used for legal reasons such as immigration, Social-Security benefits, inheritance rights, and more, as long as you order a legal siblingship test with court-admissible results. A report for an at-home peace-of-mind test cannot be used for legal reasons.

Q: How much does a sibling DNA test cost?

A: A sibling DNA test starts at $300. Total cost depends on whether you need results for personal knowledge only or for legal reasons. A sibling test requires considerably more extensive analysis, which is why it costs more than a paternity test.

Q: How does this test work if it’s unknown whether the possible sibling is a half- or full-sibling?
A: If it’s unknown whether the possible sibling is a full or half, we first test to see if there’s a biological relationship. If there isn’t, the testing is over. But, if a relationship is determined then we can do a full-sibling test request of the customer. In case there might be a cousin relationship, the sibling DNA test is not the right test to do.
Q: How do I understand results for a sibling DNA test?

A: Understanding results for a sibling 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 full-sibling test, the result could be understood as: “There is a 92% probability that the persons tested share a full sibling relationship.”

Q: My cousin could be my sibling. Can we do this test?

A: No, we cannot perform a sibling test if there might be a cousin relationship. 

Q: Is this sibling DNA test 100% clear?

A: Understanding results for a sibling DNA test is a little tricky since there can never be a straight yes or no answer in relationship testing. Calculation for relationship such as grandparent, avuncular (aunt/uncle), and siblings involve statistics, and a probability of relationship is given as a percentage in the report.

  • 90% or higher: the sibling relationship is supported by DNA testing
  • 9%-89%: inconclusive result, and additional parties need to be tested
  • Below 9%: the sibling relationship is not supported by DNA testing

If probability of relationship (PRI) of 92% is given for a full-sibling test, the result could be understood as: “There is a 92% probability that the persons tested share a full sibling relationship.”

Still have questions about the Sibling DNA Test? Please contact us.