What is sibling DNA testing?
A Sibling DNA test determines the statistical probability that two or more individuals are or are not biologically related as full or half brothers and/or full or half sisters.
Sibling DNA testing is the recommended option in situations where the suspected biological father is not available to make a determination of relationship with a standard paternity test. The sibling test establishes paternity (or maternity if needed) through the alleged father’s (or mother’s) suspected children. Our testing will show the findings based on each person’s DNA profile of whether they are biologically related to each other.
A sibling test may be needed due to the suspected father’s death, incarceration, refusal, or some other unavailability to take a paternity test. It may also be done when the need to be discreet when learning if two siblings share the same father without his direct knowledge. A maternal sibling test may also be done to answer the question of whether another person has the same biological mother. This is usually done due when a child was given up for adoption, or there are other circumstances where the child and mother were separated.
Legal sibling DNA test results are often required to obtain Social Security survivor benefits. This usually happens when the biological father of one child is not in question and a mother needs to prove that the other child has the same father. Legal DNA tests are also often performed to provide evidence of biological relationship for U.S. immigration applications.
Full sibling and half sibling DNA tests
What makes two or more children either full-siblings or half-siblings is how much DNA they share. Each of us gets half our DNA from our mother and half from our father. Full siblings have the same biological mother and the same father. These siblings get all of their genetic information from the same two people, and they share 50% of the same DNA.
Half siblings only share DNA from one common parent, and share 25% of the same DNA as their brother or sister. A half sibling shares the same percentage of DNA with their brother or sister as with a grandparent. They also share this same amount of DNA with an aunt or uncle. First cousins share just 12.5% of the same DNA, second cousins 6.125%, etc.
Choosing the most accurate DNA test to answer your questions
You have two options to choose from when you order a your DNA test:
Full Sibling vs half sibling DNA Test. In this type of sibling test, the DNA of two (or more) known siblings who share the same biological mother have their DNA compared. This will determine the probability, or likelihood, that they have the same biological father. When two or more siblings have both the same mother and same father, they are full siblings. For these tests, we recommend that when possible, samples from the biological mother also be tested to strengthen the results. This test is generally performed as a full sibling vs half sibling test, however it can also be done as a full sibling vs unrelated test. This would determine the probability that they have the same biological mother and father, compared to being completely unrelated. This is most frequently asked for when dealing with U.S. immigration cases, in which one person is a U.S. citizen who is sponsoring a suspected sibling who is applying for an immigrant visa.
If the mother’s DNA sample is not available, the DNA samples of only the siblings can be processed, and the test can still be performed.
Half Sibling vs no sibling relationship DNA Test. In these sibling tests the DNA of two, or more, possible siblings, who have different biological mothers, are compared to determine the probability, or likelihood, that they have the same biological parent (usually the father, however we can also test to determine if they share just the biological mother as well).
If you are looking to determine if you are a half sibling (sharing only one parent) it is helpful to have the mother of one of the alleged siblings submit a DNA sample. These tests are processed as half sibling vs unrelated tests. Using the DNA of the mother allows us to eliminate the mother’s portion of the DNA from each sibling’s genetic profile. We can then focus only on the other parent’s contribution to the genetic code. Including a mother’s DNA sample may help produce a stronger result in some cases.
If you would prefer to not include the mother’s DNA, Journey Genetic Testing can still perform the sibling analysis.
There is no additional cost to include one mother’s DNA sample with the initial testing.
Journey Genetics Testing’s home sibling test uses the same 24 genetic markers, laboratory standards, and produces the same results, as our AABB accredited legal sibling test. Our results for home testing can be trusted as 100% valid and accurate.
Sibling DNA Test FAQ’s
DNA testing to determine siblingship is very accurate. Our labs run all DNA tests twice to confirm results, and the answers we provide are 100% accurate based on the DNA profiles of those being tested.
Our sibling DNA test is the most accurate way to confirm or deny Ancestry.com ®, 23andMe.com ®, or MyHeritage.com’s ® genealogy reports. These heritage & ancestry companies use a linited database to indicate that you may have found a surprise sibling, but most importantly our testing can prove or disprove the findings in almost every case.
It takes 1-2 business days to complete testing and post results for a standard DNA sibling test, once the lab has received all tested parties’ samples.
Results will be delivered to the email address on the order form. They are delivered in a secure manner and are in a PDF format. They can be opened and viewed, printed, or forwarded depending on your choice to share the information. Only the ordering party, or designated email(s) will receive a copy of the report.
We also provide a booklet that explains in more detail some of what you may see on your report.
USPS Priority mail is our primary method of sending printed sibling test results, if requested at the time of the order.
We maintain your privacy every step of the way. All results and information are deleted from our system 30 days after the results are delivered to you (we keep the reports for 30 days in case you have any questions). We never sell or give your information to anyone, including government and private/public databases. No one will ever know this test was done unless you provide them the information.
DNA testing is not covered by health insurance or Medicaid because it is not a “medically necessary procedure.”
Yes. If the mom can not, or does not want to be tested, we can still perform a sibling test. A “motherless” test may require more extensive analysis to produce the strongest results, but the results that are delivered to you are just as accurate as those of a standard sibling test.
Yes! It is possible to have a DNA “paternity test” without the father’s direct involvement by using possible or known siblings. In these sibling tests, the DNA of two individuals who either share the same biological mother, or have different mothers, are compared to determine the likelihood that they have the same biological father.
Full siblings share around 50% of their DNA, half-siblings around 25%
It is not likely, as cousins share 12.5% of the same DNA and half sibling share twice that amount of genetic material. In rare situations, a double cousin may show positve as a half sibling. Double cousins are those who share all of their grandparents but none of their parents.
DNA test accuracy
Our DNA testing for sibling relationships is composed of 50% more specific genetic markers than the DNA industry standard. We have chosen not to offer lower marker testing because of our concerns regarding the accuracy of the results. This allows us to deliver results that are the most accurate available (based on the genetic samples provided).
It is important to understand that, unlike a traditional paternity test in which samples of the alleged father and child are both tested, a sibling DNA test is not an exclusionary test. This means that the results are based on the probability of the relationship. Our sibling test is a 24 marker test, which is over 1,000 times more powerful than the DNA industry standard of 16 genetic markers.
Even with the high number of genetic material that is examined in a sibling test, there may be a small percentage of cases where it may not always be possible to obtain a conclusive result in a DNA sibling test. This is, in part, because the random pattern of DNA inheritance and the sharing of genetic markers between two siblings is not the same as that between a parent and child.
In a sibling DNA test, it is possible to evaluate a generic probability in such a way as to produce a numerical probability that has the same degree of certainty consistently. However, this also depends upon who is available for testing as well as the specific type of sibling relationship being tested. As a general rule, the more genetic information available, the stronger the probability of the relationship that is declared. Half sibling and full sibling test results are written in non-scientific language and are easy to understand.
Can cousins be tested to see if they are half siblings instead?
A half sibling and a known first cousin would share a similar amount of DNA (25% for the half sibling, and 12.5% for the first cousin). DNA probability indicators are unable to distinguish between the two without the chance of a false finding in some cases. If you and your alleged sibling share an underlying relationship (cousins,etc), DNA testing will not be able to determine with 100% accuracy if you are also siblings. The best option for testing in a situation like this is to have a paternity test between the alleged father and his suspected child. If there is no possible way for a paternity test to be performed, we can do the half sibling testing with the understanding that a false positive, or an inconclusive result, may be found in about ten percent of the cases where these relationships exist.
HOW MUCH DOES THE TESTING COST?
A DNA test may well be the most important test you will ever take. We guarantee the highest quality testing at the most affordable prices. We process thousands of DNA samples every year for lawyers, physicians, adoption agencies, and private individuals.
The price for sibling DNA testing includes our DNA collection kit sent to you by USPS Priority mail, all necessary DNA collection supplies, a prepaid mailer for returning your samples (orders within the USA only), all lab processing fees, and results from our AABB accredited DNA testing lab in as little as one business day. If you do not want a kit sent to you for privacy or other reasons, we also allow the option to make your own kit and will email you a case number and step-by-step instructions for collecting and sending your DNA samples to our lab for processing.
|Cost||Number of People Testing||Processing Time|
|$119||2 siblings||1-2 Business Days|
|$119||2 siblings + one mother||1-2 Business Days|
|+$100||Each additional sibling or additional biological mother||1-2 Business Days|
|+$100||Non-standard DNA Sample (per sample)||1-5 Business Days|