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Sibling DNA Test

Are you really brother & sister?

A sibling DNA test determines whether two people share one or both biological parents. It is the most common path forward when the alleged father can not be tested directly, whether he is unavailable, deceased, in another state or country, or chooses not to participate. We process every sample through an AABB-accredited lab, with an optional legal version for court use.

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~99.8% accuracy AABB-accredited lab Legal version available 3–5 business days
When a Sibling Test Makes Sense

The most common reason families choose this test.

Sibling testing exists because life is complicated. The alleged father is not always available, willing, or even alive. When that is your situation, sibling testing offers a real path to a real answer.

Father is not available

He may be in another state or country, no longer in contact, or simply unreachable. A sibling test gets you an answer without him.

Father is deceased

For inheritance, social security, or simply wanting answers after a loss, sibling testing lets you confirm a biological relationship without the father present.

Father refuses to participate

Sometimes the father will not consent to testing. If you have access to one of his other children, a sibling test is the way forward.

Confirming full vs. half siblings

Two people may know they are related but want to confirm whether they share both parents or only one. Sibling testing answers that exactly.

Inheritance & estate matters

When an estate case requires proof of biological relationship and the father is unavailable, a legal sibling test is widely accepted.

Reconnected adult siblings

For adults who suspect (or just learned) they may share a biological parent, sibling testing offers a discreet, private way to confirm.

How a Sibling Test Works

Simple, accurate, statistically strong.

Unlike a direct paternity test, sibling testing is probability-based. The lab compares DNA markers across both siblings and calculates how likely it is that they share one or both biological parents.

01

Both siblings provide DNA samples

A simple cheek swab from each person. Painless, quick, and collected by an AABB Certified Technician at a location of your choosing.

02

Optional: include known mother(s)

If the known biological mother of either sibling is available, including her sample significantly strengthens the result. We recommend it whenever possible.

03

Lab compares DNA markers

An AABB-accredited lab analyzes shared genetic markers between the participants using STR (Short Tandem Repeat) analysis, the same method used in paternity testing.

04

Probability index calculated

The result is reported as a probability. A high probability (typically 99% or above) supports a biological sibling relationship; a low probability indicates the participants are unrelated.

05

Full or half sibling distinction

The test can also distinguish whether siblings share both parents (full siblings) or just one (half siblings), depending on which samples are included.

06

Results in 3–5 business days

Delivered securely via email. Hardcopy mailed results available for $25. Legal results carry a notarized stamp for court use.

About the Accuracy

Why sibling tests are probability-based.

A direct paternity test compares a child to their alleged father, and the answer is essentially binary: 99.99% match or 0% match. Sibling testing is different because there is no single, direct genetic comparison to make.

Instead, the lab looks at how many DNA markers two siblings share and calculates the statistical likelihood of that pattern given a biological sibling relationship. Around 99.8% accuracy is achievable, and the result is stronger when:

  • Both siblings are tested (not just one against a sample)
  • The known biological mother of either sibling is included
  • More than two siblings are tested at once (if available)

If maximum certainty matters for your situation, ask us about including additional family members. We will recommend the strongest path for your specific case.

Sibling DNA Test
  • ~99.8% accuracy
  • Works without the father
  • AABB-accredited lab
  • Legal version available
  • Distinguishes full vs. half siblings
Direct Paternity Test
  • 99.99% accuracy
  • Requires the father
  • AABB-accredited lab
  • Legal version available
  • No sibling info
See Legal Test →
What's Included

The same standards as every test we offer.

Mobile collection, certified specialists, AABB-accredited lab processing, and clear results.

Mobile collectionWe come to you, anywhere within 20 miles of 92585. Extended areas quoted upfront.
AABB Certified TechnicianYour collection is performed by a trained, certified specialist.
AABB-accredited lab processingThe same gold-standard accreditation used for legal DNA tests.
Results in 3–5 business daysDelivered securely via email the moment they are ready.
Optional legal versionFull chain-of-custody and notarized results for court, inheritance, or legal use.
Bilingual supportHablamos Español. Spanish-speaking technicians available 7 days a week.
Common Questions

Sibling DNA testing, answered.

We don’t offer online booking, and that’s intentional. Before we schedule any appointment, we need to ask a few pre-qualifying questions to make sure we order the right test for your situation. For example: how many participants are being tested, who is involved, whether the test needs to be court-admissible, whether anyone is pregnant, and what location works best. Calling, texting, or emailing means you speak with a real person, not a chatbot or scheduling form. This avoids misunderstandings, makes sure your test is set up correctly the first time, and gets you to your results faster. Call or text (951) 290-7500 or email contact@paternityverified.com, 9 AM – 9 PM, 7 days a week.
The only real difference is convenience. We come to you instead of you driving to them. What people don’t always realize is that those brick-and-mortar “DNA testing” locations are not labs either, they are collection sites, just like us. They collect your sample and ship it off to an outside lab. We do the exact same thing, except the collection site is wherever you want us to show up. Same lab processing, same accreditation, same accuracy. We just remove the driving, the waiting room, and the appointment-coordination headache.
Yes, anywhere that works for you. Your home, a friend or relative’s home, your workplace, an attorney’s office, a hospital, even the parking lot of a coffee shop, library, grocery store, or any business where you can sit in your car. The collection takes about 20 minutes and we work around your privacy and your schedule. If you can be there with valid ID, we can collect there.
Approximately 99.8% accuracy. Unlike paternity testing, sibling tests are probability-based: the lab calculates how likely it is that two people share one or both biological parents based on shared DNA markers. Accuracy increases when the known biological mother of either sibling is included.
Yes. The test can determine whether the participants share both biological parents (full siblings) or just one (half siblings), depending on which samples are included. Including the known mother of one or both siblings is the most reliable way to make this distinction.
Not required, but highly recommended. Including the known biological mother of either sibling significantly strengthens the result. If she is available, we strongly suggest adding her to your appointment.
Yes. A legal sibling DNA test follows the same chain-of-custody requirements as a legal paternity test: AABB-accredited lab processing, photo ID verification, witnessed collection, and notarized results. It is widely used for inheritance cases, social security claims, and other legal matters where direct paternity testing is not possible.
When the alleged father can not be tested directly. The most common reasons: he is deceased, in another state or country, no longer in contact with the family, or unwilling to participate. If you have access to one of his other biological children, a sibling test gets you a strong answer without him.
Yes, and it actually improves the result. The more biological relatives you can include, the higher the statistical confidence of the test. Call us and we will quote your specific situation.
Most sibling DNA test results are available within 3–5 business days after samples reach the laboratory.
Pricing varies based on how many people are being tested and whether you need the peace-of-mind or legal version. Call us at (951) 290-7500 for a transparent quote. No upfront payment required.

Ready to get answers? We are here.

Call or text us 7 days a week, 9 AM – 9 PM. A real person (not a robot) will walk through your specific situation and recommend the strongest test setup for your family.

Call (951) 290-7500
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Open today · 9 AM – 9 PM · 7 days a week
Appointments scheduled 9 AM – 7:30 PM · Closed on major holidays