Accredited U.S. Laboratory
Testing is performed by an AABB-accredited U.S. partner laboratory using established relationship DNA testing methods.
Sibling DNA Test | Buy A Sibling DNA Test Kit
Sibling DNA Testing
Our sibling DNA test helps determine if two individuals are full siblings, half siblings, or not biologically related. This DNA test for siblings is often used when the alleged father or mother is unavailable for a direct paternity or maternity test. It may also be used as a brother and sister DNA test when the goal is to help determine whether two people share the same biological father or mother. Compare 34-marker and 46-marker options based on your situation, with fast accurate results from Accredited U.S. laboratories. PaternityUSA has been serving families nationwide for over 25 years with professional DNA relationship testing you can trust.
Because this is an indirect relationship test, results are based on statistical percentage of probability of between 0% and 99.99%. Fast FREE 2-way shipping included.
25+ Years of Service
For more than 25 years, we have helped families arrange paternity and relationship DNA testing nationwide.
46 Marker Testing
Higher marker testing may provide stronger statistical support in certain complex relationship cases.
Fast, Private Results
Results are delivered in 2-3 days with confidential handling of samples and secure reporting throughout the testing process.
We Offer Two At-Home DNA Tests for Siblings:
There are two factors that dramatically help a sibling DNA test, or DNA test for siblings, achieve the strongest and most informative statistical answer: adding the mother(s) and/or analyzing more markers.
24-34 Marker Test – Our standard sibling test includes the mom at no additional cost, analyzes up to 34 markers, and is competitively priced at just $125. This testing option includes fast free shipping both ways at no extra cost. This is a good option when the mom is available, and/or you want to save money.
46 Marker Test – Our 46 marker DNA test for siblings will analyze 46 markers, thus analyzes a higher number of genetic markers than many standard 20-22 markers tests, and is likewise competitively priced at $175. Our 46 marker test also includes fast free shipping both ways at no extra cost.
Analyzing a greater number of STR markers increases the statistical power of the test by providing more comparison points, which can help strengthen the likelihood ratio and reduce the chance of inconclusive results in complex sibling comparisons. Our relational DNA tests are performed using STR analysis in an AABB-accredited USA laboratory and reviewed by professionally certified laboratory scientists. DNA testing is performed in accordance with established relationship testing methodologies used in forensic DNA analysis and consistent with AABB-accredited laboratory standards.
Furthermore, relational DNA tests can help support or dispute Ancestry.com ®, 23andMe.com ®, or My Heritage.com’s ® genealogy test results. These heritage & ancestry kits use a database to indicate that you may have found a lost brother or sister, but a person-to-person relational test can help support or not support the likelihood of those findings.
It’s important to note that not all sibling DNA tests are the same. If you’re not sure which test is best for your situation, please call (877) 786-9543, and speak to one of our experienced DNA testing experts.
Our 34 Marker Test
$125
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24-34
Marker Count
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FREE
mom inclusion
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High
Conclusiveness
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FREE
2-Way Shipping
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Our 46 Marker Test
$175
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46
Marker Count
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Extra Fee
for mom inclusion
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Highest
Conclusiveness
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FREE
2-Way Shipping
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Typical Competitors
Up to $299
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16-22
Marker Count
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Extra Fee
for mom inclusion
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Variable
Conclusiveness
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Variable Pricing
on 2-Way Shipping
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How does the testing process work?
Our simple testing process guides you from ordering your DNA kit to receiving clear, confidential results, with easy sample collection and professional laboratory analysis at every step.
Order Home Sibling DNA TestOrdering & Shipping
Upon receipt of your online or phone order, we will rush you a free sterile sibling DNA testing kit that contains all the needed swabs along with a pre-paid & pre-addressed envelope to return your samples directly to lab. Tracking numbers are available both ways.
Sample Collection
Sampling is easy & painlessly done through a cheek swab by simply rubbing what looks like an oversized Q-tip along the inner cheek and gum, then inserting the swabs in the provided sample envelope.
Sample Analysis With Straightforward Results
When samples arrive at lab, you will be notified via email, and the true science begins. The lab then analyzes the genetic profiles of the possible siblings and produces a percentage of probability of the relationship. This percentage indicates the likelihood of the tested parties being full siblings, half siblings, or not siblings.
Results Delivery
At the conclusion of the test, the results are immediately emailed and/or mailed to the address on file.
Home Paternity DNA Testing Reviews
For over 25 years, families across the United States have trusted PaternityUSA for reliable DNA testing and knowledgeable client support, serving hundreds of thousands of clients nationwide with fast, confidential results.
“In my opinion I am very satisfied. I have an adult daughter that’s 24 years old now that I did not know I had. The results came in very quickly, took a couple of days, and I am very pleased with this product. If I need it again, this is what I’ll get. I will definitely recommend this to anybody that needs to do a DNA test.”
Frequently Asked Questions About Sibling DNA Testing
Get answers to common questions about sibling DNA testing, including how the test works, who should participate, and how results determine whether individuals share one or both parents. This content has been reviewed for accuracy by a DNA testing specialist with over 20 years of experience in relationship DNA testing. All testing is performed by accredited U.S. laboratories using validated genetic analysis methods.
Yes. A sibling DNA test, also called a DNA test for siblings, can help determine whether two or more individuals share the same biological father when the father is unavailable or unwilling to participate. The test compares the siblings’ DNA to evaluate the likelihood that they inherited genetic markers from the same father. Including the mother can improve the conclusiveness of the results because her DNA can be accounted for and removed from the comparison, but testing can still be performed without her. In those cases, higher-marker analysis—such as a 46-marker siblingship test—examines more genetic data than standard tests, improving accuracy and strengthening the statistical conclusion.
No. Siblings do not have identical DNA (except identical twins). Full siblings typically share about 50% of their DNA, while half siblings share about 25%, but the exact amount can vary.
No. A paternity test directly compares a child to an alleged father and can provide highly conclusive results. Sibling DNA testing is an indirect analysis and provides a statistical likelihood of relationship rather than definitive proof.
When all tested siblings are male, a Y-STR DNA test is often the most appropriate option unless the alleged father could be a related male from the same paternal line. This test analyzes the Y chromosome, which is passed nearly unchanged from father to son, meaning brothers with the same biological father will have matching Y-STR profiles, while non-matching profiles indicate they do not share the same paternal line. Similarly, an mtDNA (mitochondrial DNA) test can be used to confirm maternal-line relationships, since mitochondrial DNA is passed from a mother to all of her children, and matching mtDNA results indicate a shared maternal lineage.
Yes, DNA testing can help evaluate whether two people may be cousins, but the type of test used is important. A sibling DNA test is not ideal for distinguishing between siblings and cousins because their genetic similarities can overlap, making results less conclusive. The most reliable approach is a paternity or maternity test that includes the parent connecting the two individuals, as testing the parent directly provides clearer evidence of the biological relationship. If you are unsure which test is best for your situation, calling (877) 786-9543 to speak with a DNA specialist can help you choose the most accurate option.
Sibling DNA testing is highly accurate when performed using modern laboratory methods and proper testing protocols. The reliability of the results depends on factors such as the number of genetic markers analyzed, whether the mother is included in the test, the quality of the DNA samples, and the overall testing methodology. Higher-marker testing and including the mother typically produce more conclusive results. All testing is conducted in a U.S.-based laboratory using validated DNA technology and strict quality controls, and legal sibling tests follow chain-of-custody procedures for court acceptance. Results are reported using a sibling DNA index—values above 1.0 indicate the individuals are more likely to be siblings, while values below 1.0 suggest they are less likely related—and this index is also converted into a percentage probability to make the findings easier to understand.
Sibling DNA test results are presented using statistical values that show how strongly the DNA evidence supports or does not support a sibling relationship. These values compare the likelihood that the tested individuals are related versus unrelated.
Yes, in certain situations you may use your own Q-tips if a DNA sample must be collected immediately and waiting would risk losing the opportunity to obtain the sample. However, standard Q-tips are not ideal because they are not sterile or specifically designed for DNA collection, which can affect sample quality and reliability. For the most accurate results, a medically sealed, sterile collection kit is strongly recommended, which is why PaternityUSA provides free rush shipment of proper DNA collection kits whenever possible.
Yes. In some cases, alternative DNA samples can be used when standard cheek swab collection is not possible. Common non-standard samples include earwax, hair with the root attached, mucus from a tissue, fingernail or toenail clippings, and toothbrushes, although the suitability of these items depends on their condition and how they were handled since DNA quality can vary. Because these samples require special handling and testing considerations, it is recommended to speak with a DNA specialist first to determine the best approach and improve the chances of accurate results.
Yes. All testing is performed in fully accredited laboratories and overseen by qualified, experienced PhD-level geneticists. AABB accreditation requires strict scientific standards, documented procedures, and professional oversight at every stage of the testing process, ensuring samples are properly handled, results are scientifically valid, and reports meet both medical and legal reliability standards.
Once you place your order, your sibling DNA test kit is shipped directly to you. Orders placed before 12:00 PM Eastern Time typically ship the same business day with free, trackable USPS delivery to physical addresses within the contiguous United States, Monday through Friday, while orders placed later ship the next business day. Expedited shipping options are available during checkout for faster delivery, but a physical address is required since expedited shipments cannot be delivered to PO boxes.
If siblings are located in different places, testing can still be completed easily. During the ordering process, you can provide an additional shipping address and a separate collection kit will be sent to the other participant. Each kit includes unique reference numbers and barcodes so the laboratory can correctly link all samples when they are received. Please note that secondary kits cannot currently be shipped to New York or internationally; if you require international shipping or have special circumstances, a DNA specialist can help review your available options.
Yes. A legal sibling DNA test can be used for official and court-recognized cases when proper procedures are followed. Legal sibling testing requires strict chain-of-custody procedures and is commonly accepted for matters such as child support, visitation, adding or correcting a name on a birth certificate, estate and probate cases, wills, and other legal situations where proof of a biological sibling relationship is required. If testing is needed specifically for immigration purposes—such as for USCIS, ICE, Department of Homeland Security, embassy cases, passports, or a Consular Report of Birth Abroad (CRBA)—special immigration testing requirements apply, and the test must be coordinated through an AABB-accredited immigration DNA testing provider to ensure the results are accepted by the requesting agency.
Yes. It is possible for siblings to have different biological fathers, a situation known as heteropaternal superfecundation. This can occur when a woman releases more than one egg during the same cycle and each egg is fertilized by a different father. A sibling DNA test can help determine whether siblings share the same biological father by comparing their genetic markers and calculating the statistical likelihood of a shared paternal relationship.
Most sibling DNA test results are completed within 2–3 business days after the laboratory receives all samples. Each test kit includes a free, pre-addressed, trackable return envelope so samples can be sent back to the lab quickly and securely. Once testing is complete, results are finalized and released without unnecessary delays.
Blog Articles About Sibling DNA Testing
Learn More About Sibling DNA Testing
Can Two Full Siblings Have Different DNA Results?
The short answer is YES. Even full siblings can have unique DNA findings. Even though you share parents, how your DNA gets divvied up allows for variation in the DNA pr…
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March 25, 2024
What Is The Best DNA Test To Tell If Two Brothers Have the Same Father?
If you've got two brothers and aren't totally sure if they have the same biological father, a Y-STR DNA test can provide the answers you need. But testing brothe…
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How Reliable Are Sibling DNA Tests?
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Can A DNA Test Determine If Siblings Have The Same Father?
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Can Sibling Tests Determine Between Cousins and Siblings?
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What is the best DNA test for half-siblings?
Are you pondering the puzzle of half-siblings and wondering how to unlock the truth hidden within your family's DNA? With so many options out there, which test is the b…
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Are you curious if your sibling is your full or half sibling? Look no further than PaternityUSA for reliable, affordable, and comprehensive sibling DNA testing services…
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Can a DNA test be done with a strand of hair?
When a DNA testing participant is unwilling to participate or is unable to provide a mouth swab for their DAN test, the question: " Can a DNA test be done with a strand…
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Why buy your DNA test from PaternityUSA?
PaternityUSA offers relational DNA testing services allowing clients to evaluate whether a biological relationship may exist, such as paternity , sibling , grandparent …
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What is needed for a sibling DNA test?
A sibling DNA test is now more affordable and accurate than ever. Depending on your unique situation, sibling DNA testing answers questions about paternity or maternity…
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Can you get a DNA test to see if you are full siblings?
In this article we will unlock some of the nuances of relational DNA testing to better understand how full sibling DNA testing works. We are contacted daily by clients …
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March 5, 2024
Can a DNA test prove siblings have the same father?
One of the most asked questions regarding DNA testing for siblings is, "Can a DNA test prove siblings have the same father"? The simple answer is Yes, it can. Sibling D…
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How Accurate is Sibling DNA Testing?
How Accurate is Sibling DNA Testing? If you find yourself in a situation where you need to confirm a sibling relationship, who should you buy your test from? Wit does n…
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Private DNA Testing: PaternityUSA.com Ensures Ultimate Privacy
Today's digital age has made privacy become a hot topic. When using social media or going online to shop for a a product we must constantly remember just how important…
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Siblingship DNA Testing, Does It Work?
DNA testing between two or more people who believe they could be siblings is referred to as sibship, or siblingship testing. This type of relational test compares the g…
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March 1, 2024
