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Frequently Asked Questions About A Sibling Test

This FAQ page provides comprehensive information about sibling DNA testing, including how it works, when to use it, and what to expect from the process. If you’re looking for answers to your questions about sibling DNA tests, you’ve come to the right place. Our legal sibling testing services are available for court cases or other legal purposes. Contact us today to learn more about our sibling DNA testing services.

How Conclusive Are Your Sibling DNA Tests?

The results of a sibling paternity test are shown as a probability percentage. This indicates whether the genetic profiles acquired can confirm the presence of a relationship. Results demonstrating a probability of 91% or higher are deemed as definitive proof that the relationship exists. Conversely, a probability of less than 9% establishes that the genetic evidence does not support the existence of the relationship.

Can DNA Tell Which Brother Fathered A Child With A Sibling Test?

The answer is “Yes” in almost every situation. A sibling DNA test can determine which brother is the biological father of a child, if you include the DNA of the mother. Every child has genetic contributions (46 chromosomes) 23 chromosomes from the mother and 23 chromosomes from the father.

Can Your DNA Test Prove We Are Half Siblings?

Yes, our DNA test can prove you are half siblings. In fact, DNA testing is the most scientific and accurate way to prove that two or more individuals are biologically related. Half-siblings share only one biological parent, either the mother or father.

Can I Use The Results In Court?

We offer AABB accredited legal sibling testing which is valid in cases for child support, parenting time, birth certificate name changes, probate, and wills, as well as many other legal circumstances. A legally admissible DNA test requires some extra steps, however the final results will be the same.

Can You Tell If We Are Siblings Or Cousins?

It depends. Since half siblings share 25% of the same DNA, and first cousins share 12.5%. Depending on if a mother’s DNA is available to test as well, there may be other testing options that would give stronger results. In these situations we encourage you to talk with one of our Genetic Consultants at 1-855-362-5224, or email us at and we can offer advice on your unique situation.

Can I Test Something That Is Not A Mouth Swab?

Yes! Some commonly used items that are not a mouth swab include ear wax, hair (must have the root ball attached), mucous on a tissue, finger or toe nail clippings, and toothbrushes. You can learn more about these “non-standard” DNA samples by clicking on Alternative DNA Samples, or call us a 1-855-362-5224.

How And When Will I Be Receiving My Sibling DNA Test Kit?

If you place your order before 2:00 PM PST, we will send you a sterile DNA collection kit by Priority mail and email you a USPS tracking number. We ship Monday through Friday to physical addresses in the USA Orders received after 2:00 PM PST ship the following business day. Depending on your location, USPS delivers Priority mail within 1-3 business days.

How Fast Can I Get My Sibling Test Results?

Once the lab has all of the samples available for sibling testing, we will have the results for you in 2 business day in almost every single case. All DNA tests for siblings are performed twice, to validate the findings. We do not charge any extra fees for this service.

Do I Need A Mother’s DNA For This DNA Test?

You can still do DNA testing without a mother’s DNA. What if you can’t provide her sample with the siblings’ tests? We can still proceed, but we might need to examine more genetic markers. We begin with 24 markers, but sometimes we use up to 46 for stronger results. While this isn’t common, it’s possible. We’ll determine the need during testing. Additional markers might take an extra lab day, but no extra charge. These added markers aim for the best results.

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