Sibling DNA Tests: The Ultimate Guide

If you need to know how to do a sibling DNA test, this is the ultimate guide. In this article, we explain what a sibling DNA test means, what you need to look for in a test, and which are some of the best options on the market.

Although home DNA testing has grown in popularity because of its ability to provide information about ethnic ancestry, many families have also relied on DNA test results for sibling or other familial relationship determination.

If you're searching for a sibling test that will confirm your relationship with a potential brother or sister, there are several options to choose from. The best test for you depends on your situation, so read on to find out more about the best sibling DNA tests of 2020 and what information they can provide.

Sibling DNA Testing: FAQs

What is meant by a sibling DNA test?

Generally speaking, any DNA test which uses genetic markers to measure relationships can be considered a sibling test, because it can be used as an indicator that a relationship exists.

With that in mind, your reason for testing will determine what kind of test you'll need. Two types of test exist: legal relationship testing, and ancestry/peace of mind testing.

If you need to prove your siblingship in court, you'll need to rely on tests intended for legal relationship testing. They typically have a processing turnaround time of only a few days, and the results are admissible in court cases.

Alternately, if your desire to test is simply for your peace of mind or as part of an exploration of your family's genealogy, you may prefer to opt for one of many popular DNA kits like AncestryDNA, 23andMe, or Family Tree DNA, which provide an ethnic ancestry breakdown and access to a database of genetic relatives. Explore and compare the best DNA testing kits on the market.

Do siblings share identical DNA?

No, siblings do not have identical DNA. The reason why is a process called genetic recombination. Unlike typical cells, mature sperm and egg cells each have 23 chromosomes; these combine to form a full 46 chromosomes in a zygote.

The reduction in chromosomes happens when the cells are created, as the chromosomes exchange certain parts of genetic material and then form either an egg or a sperm cell. The parts that are passed on are unique to each egg or sperm cell, which means that even two full biological siblings only actually share about half of the same DNA. If there's a significant degree of genetic diversity in your family's recent history, the effects may be a bit more obvious.

In other words: even fraternal twins will have genetic variance due to recombination, and can expect to have test results that aren't a perfect match.

Does it matter which brand of sibling DNA testing is used if the results are needed to prove a relationship in court?

Yes, your choice of test does matter in this case. Not all DNA sibling tests are admissible in court, so it's important to choose a kit which will provide legal proof of your relationship. Wondering which test results can be used in court?

• BioGene
• AncestryDNA
• LiveWell*
• GenTrace*

* - an additional charge is required for legal-grade testing

Can a DNA test actually prove my sibling relationship?

You'll be happy to know that, yes, a DNA test can confirm or deny your sibling relationship. Your test results will use genetic markers to determine how much DNA you share with the other person or people being tested, allowing for the extrapolation of a genetic relationship. While a DNA test can tell you whether or not someone is your sibling, it can not tell half-siblings which parent is shared if this information is unknown.

Will a DNA test tell me if the person I'm testing is a full sibling, half sibling, or unrelated?

As we mentioned, your DNA test relies on genetic markers to determine the nature of your relationship with the other person or people being tested. The number of markers you share with someone else can be used as a measure of your projected genetic relationship. As such, it is possible to know how closely you are related through these results.

Is it possible for me to find siblings I didn't know I had through DNA testing?

If you take a DNA test that promises access to a database of DNA matches, you may locate family members you did not know you had. In some cases, this may include a full or half-sibling you were previously unaware of.

Depending on your background, it may be important to keep in mind the delicacy of the situation, especially if your parents are still living. If you do identify someone thought to be an unknown sibling, proceed cautiously with this sensitive information.

How can I maximize the accuracy of my sibling DNA test?

In order to get the most accurate results out of your sibling testing, your best bet is to have both siblings and their theoretical shared biological father or biological mother take tests. The process of determining a biological relationship is made much easier by the ability to compare it against parental DNA, as it's easier to tell whether or not siblings have both inherited 50% of their DNA from that parent.

How are sibling DNA tests administered?

Fortunately, there's no complex procedures required to take a home DNA test. Generally speaking, each person being tested will be asked to submit a genetic sample in the form of saliva or a cheek swab. This is painless and hygienic, making the sample collection process simple.

One interesting thing to note is that test company BioGene is able to accept alternative sample types, including a fingernail clipping, hairbrush, or toothbrush, among others. This can allow you to test someone without their knowledge, and may allow you to test DNA even after someone has passed away.

How long will it take for me to receive my results?

The amount of time it will take for you to receive your results varies by company. Tests that are designed to measure only your genetic relationships tend to have much faster turnaround times, with some services advertising results in as quickly as one day after samples are received.

If you opt for peace of mind testing like AncestryDNA, 23andMe, or FTDNA, you'll be looking at a much longer processing time. The latter has a processing time of six to eight weeks, while the former two process samples in about four to six weeks.

Comparing the Tests

1. LiveWell

Best for easy ordering

• Number of markers tested: 23
• Processing time: 3 - 5 days
• Admissible in court: For an additional charge
• Type of sample collection kit: Cheek swab
• Results offered: Relationship testing

Navigating your genealogical journey is tough enough without wrestling with tech if it's not your forte. LiveWell has created a website that makes it easy for customers to "get in and get out", allowing you to quickly order up the tests you need.

Once they arrive, a simple cheek swab is all that's required to collect your samples and send them off for processing. The price of a test includes two swab kits, so keep this in mind when ordering -- this kit is only intended to compare your relationship with one other person.

After you've sent in your samples, LiveWell processes them at a lab that's AABB, A2LA, and CAP certified. The turnaround time for your results is quoted as three to five days; this is longer than some relationship testing services, but not by much at all. You can opt to receive your test results by either email or hard copy/snail mail, another bonus for people who prefer to keep sensitive matters offline. Unfortunately, hard copy results do demand an extra fee.

Your results, which are easy to interpret, will tell you if you and the other person being tested are full siblings, half-siblings, or unrelated. However, these results will not be admissible in court. If you require legally admissible results, you'll need to spring for a test that's suitable for legal proceedings to the tune of an extra $100.

Pros

• It's not confusing -- ordering, testing, and receiving results are all simple even for a novice
• The lab is highly accurate and certified and the turnaround time is speedy

Cons

• If you need results that will hold up in court, you'll need to pay an extra $100 for legally admissible relationship testing
• If the other person being tested doesn't live with or near you, you're left with the responsibility of shipping their test kit to them

2. BioGene

Best for results processing time

• Number of markers tested: 24
• Processing time: One business day
• Admissible in court: Yes
• Type of sample collection kit: Cheek swab, but alternative samples also accepted
• Results offered: Relationship testing

If you're in search of a sibling DNA test that's quick, discreet, and legally admissible, BioGene might just be what you're looking for.

This test relies on a simple cheek swab test to collect DNA samples, but they're also willing to accept alternate sample types. Hair from a hairbrush, a toothbrush, a fingernail clipping, and other biological items can potentially be used to extract DNA. In delicate circumstances, this can allow you to test someone's DNA without their knowledge, or potentially even after someone has passed away.

It's important to note that in eight states, testing someone's DNA without their consent falls under a branch of bioethics law called gene theft. Doing this in Alaska, Florida, New Jersey, New York, or Oregon may be civilly or criminally prohibited, and you can be sued for gene theft in Minnesota, New Hampshire, and New Mexico.

In another measure of discretion, if you need to avoid having a kit physically sent to your address, the company allows you to select the "make your own kit" option. They will instruct you on how to create a DNA sample and where to send it, ensuring maximum privacy for you.

BioGene's basic price includes DNA tests for two siblings, but additional tests can be ordered at an extra cost. A helpful feature offered by this company is the ability to ship each test to an individual address rather than directly to you for redistribution. Adding additional kits to your order is relatively low-cost and the price of each includes USPS priority shipping, making BioGene an ideal pick for a larger group of people requiring legally admissible sibling DNA tests.

Pros

• They're masters of discretion, allowing you to eschew the use of a physical kit if desired and accepting alternate samples to facilitate non-invasive testing
• Adding additional kits to the contents of the base kit is relatively inexpensive and includes shipping cost to a separate address

Cons

• Though the test facilitates the administration of a DNA test to an unwitting party, this is not legal in all jurisdictions and should be considered very carefully

3. GenTrace

Best for easy-to-read results

• Number of markers tested: 16
• Processing time: 3 - 5 days
• Admissible in court: For an additional charge
• Type of sample collection kit: Cheek swab
• Results offered: Relationship testing

Trying to test a larger group of potential siblings who aren't geographically adjacent can pose a number of issues. Fortunately, GenTrace simplifies the process a great deal by allowing you to test up to seven of your potential siblings, shipping each of their test kits to a unique address.

The company uses a simple cheek swab test to obtain your results, but they also assert on their website that if it's necessary to use a hair or other biological sample for a deceased relative, it may be acceptable. The turnaround time of three to five days is around the industry average. All of the tests disseminated will have a bar code that connects them. GenTrace tests these kits, then releasing the results to all parties via email at the same time.

They use an index value to make it easy to determine whether or not the person or people being tested are your siblings. An index value of 1 or more means that a sibling relationship is likely. If it's under 1, you're not likely to be related. Half and full sibling relationships are tracked through a different index, but these relationships can be revealed as well.

There's one downside here, which is that the results of these tests are not legally admissible. If you need your sibling DNA test for court proceedings, you'll need to shell out some extra cash for their court-admissible test.

Pros

• Testing larger groups of potential siblings is easy, as kits can be individually shipped to up to seven addresses
• A simple index value used to indicate sibling relationships makes these test results easy to read, even for beginners

Cons

• Your GenTrace results won't be legally admissible unless you shell out for their court-admissible test, which is quite a bit pricier than the base kit

4. Genovate

Best for affordability

• Number of markers tested: 46
• Processing time: 1 - 3 days
• Admissible in court: For an additional charge
• Type of sample collection kit: Cheek swab
• Results offered: Relationship testing

Relationship confirmation from an affordable, thorough test with a quick turnaround time is a very attractive prospect, and that's exactly what Genovate delivers. Their relationship test measures 46 markers, almost twice as many as similar sibling DNA tests.

They claim a turnaround time of between one and three days, which is a bit quicker than competitors. They also keep their prices a few dollars lower than similar kits on average, which makes them a good option for the budget-conscious shopper.

Of course, no test can deliver it all -- Genovate's base tests aren't admissible in court. If you're confirming a sibling relationship for legal reasons, you do have the option of choosing a legally admissible test for purchase, but you'll spend an extra $100 on average.

Testing a larger pool of potential siblings? You can buy tests for up to seven siblings on the Genovate website. They also offer the convenience of allowing you to ship to multiple addresses, saving you from extra hassle and postage costs. The quick turnaround time and low base kit cost make it an ideal pick for a duo or group looking for simple relationship confirmation for non-legal reasons.

Pros

• The base kit price is a few dollars lower than the average competitor
• The turnaround time is also a couple days faster than average

Cons

• The base test is not legally admissible, and a court-approved test is significantly more expensive and may require a physical office visit

5. MyForever

• Number of markers tested: 46
• Processing time: 2 - 3 days
• Admissible in court: No
• Type of sample collection kit: Cheek swab
• Results offered: Relationship testing

Striking a balance between accuracy and speedy processing time, MyForever is another service that's best for a duo or group who are looking for non-legal relationship confirmation. The test analyzes 46 genetic markers to identify full or half-sibling relationships, and your results will be available in two to three days, which is slightly faster than the industry average.

The painless cheek swab test, which can be administered to users of any age, can be sent out to individual test-takers rather than shipped in bulk for your convenience. As is the case with most tests, all takers will receive their results via email within the stated time window. If you'd like a physical copy of your results instead or as well, that is an option, but the processing time quoted does not apply to receiving results by mail.

You may have noticed that we mentioned non-legal relationship testing -- that's because MyForever is another test which doesn't offer a legally admissible result from its base kit. The company's site notes that a legally-admissible test is available at additional cost, but administration of the test will require a visit to one of their physical offices for lab work.

Pros

• Results have a quick turnaround time, are measured against a high number of genetic markers, and can be received in a physical format if desired
• Tests can be shipped to multiple potential siblings individually, saving you the hassle of handling distribution to a far-flung crowd

Cons

• The results of MyForever's base test aren't legally admissible -- for a court-approved test result, you and your potential siblings will need to visit one of the company's physical offices

6. Family Tree DNA

• Number of markers tested: 37
• Processing time: 6 - 8 weeks
• Admissible in court: No
• Type of sample collection kit: Cheek swab
• Results offered: Family ancestry, genetic ethnicity, living relative comparison

If your reason for comparing your DNA with a potential or definite sibling is mainly for peace of mind or as a part of your genealogical hobby, you may find that Family Tree DNA is just right for your needs. Their Family Finder test can be used to identify sibling relationships, and as a bonus, you'll both receive interesting information about your genetic ethnicity and access to a database of living relatives.

As their test kit isn't explicitly intended for relationship testing, there are a few differences between this and a typical sibling DNA test. First, FTDNA tests are only intended to test one person. In order to compare a relationship between two siblings, you'll need to purchase two tests, and the company will not ship them to two different addresses for you.

If placed as one order, shipping one kit costs $9.99, with an extra $4.99 added for each additional kit. This means that if the person the kit is intended for lives in your area, you may be able to save a few dollars dropping it off. Otherwise, simply placing a second order and shipping the test to their home rather than making the trip yourself evens out cost-wise.

As FTDNA offers far more dynamic results than a simple relationship test, you'll be waiting six to eight weeks for your results. When they arrive, you'll be able to compare your relationship -- or lack thereof -- to your potential sibling through the site's living relatives database. You'll also be able to see a breakdown of your genetic ancestry, interact with a database of other living relatives, and compare a diagram of your chromosomes to those of people you're related to.

As noted, this test is not court-admissible, so it's not ideal for those testing for legal reasons.

Pros

• You'll be able to discover any potential sibling relationship with the person you've tested with as well as interesting insight into your ancestral ethnicities
• The results offer you the potential to connect with a number of other living relatives through the site's matching database

Cons

• It's not ideal for those testing for legal reasons, as the turnaround time is 6 - 8 weeks and the results aren't admissible in court

Read our complete Famility Tree DNA review.

7. 23andMe

Best for health risk screening

• Number of markers tested: 700,000
• Processing time: 4 - 6 weeks
• Admissible in court: No
• Type of sample collection kit: Cheek swab
• Results offered: Family ancestry, genetic ethnicity, living relative comparison, health insights

23andMe is a company that's hard to miss, as they were one of the first to establish a presence in home DNA test kits, and were the first to offer health insights as part of their results. They've established a physical sales presence in approved retailers, making them one of the only top-name tests you can buy in a store.

The test results offered by 23andMe also include a database of living relatives, which means that it can function as a sibling DNA test. While results can indicate the presence of a sibling relationship, sussing out whether your relative is a full or a half sibling will come down to examining centimorgans and shared matches -- this can be complex for a novice, but it's not impossible to do.

Shipping to multiple addresses isn't complex with 23andMe, because standard shipping is always free through their website. You'll have to place an order for each person you want to send to in order to distribute tests without shipping them yourself, but it won't cost you any extra money.

The cost of each kit also offers plenty of additional information that can be both interesting and helpful to peruse, including insight into genetics-based health traits, a breakdown of your ethnic ancestry, and a database of other living relatives to peruse.

Pros

• It's one of the most popular DNA tests on the market, so you'll be able to identify sibling relationships while also accessing info on ethnicity and traits
• Shipping is free, so you can send tests to as many potential siblings as desired without additional cost

Cons

• Because the test has more in-depth results, the processing time takes several weeks

Read our complete 23andMe DNA review.

8. AncestryDNA

Best for genealogical research

• Number of markers tested: 700,000
• Processing time: 4 - 6 weeks
• Admissible in court: Yes
• Type of sample collection kit: Saliva sample
• Results offered: Family ancestry, genetic ethnicity, living relative comparison

If your quest for a sibling DNA test is part of a larger effort to catalog your family's genealogy, you're probably already familiar with what Ancestry has to offer both as a website and via DNA testing. The AncestryDNA test rivals 23andMe as the world's most popular DNA test, and their database of living relatives with predicted matches and ethnicity and chromosome comparison means that the kit can pull double duty as a sibling DNA test.

As with other ancestry testing kits, AncestryDNA is sold individually, so you'll need a kit for each person you want to test. Shipping the first kit costs $9.95, and shipping for additional kits is $4.95, but all must be shipped to the same address. If other people you're testing aren't in the area, it may be worthwhile to simply place a second order under the assumption that it would cost an amount equal to what was saved if you had to send the test yourself.

The simple saliva sample test is easy to administer, but it's not as quick for younger children than a basic cheek swab test. Results are processed in an industry average of four to six weeks, and are received via email; a text alert can also be received if you opt-in through the website.

In your results, you'll find an interactive breakdown of your ethnic ancestry as well as a database of living relatives that, if you are related, will contain your potential sibling. You'll be able to view your DNA and ethnicities side by side, learn of a projected sibling relationship, and potentially extrapolate which parent is shared between you if that information is unknown.

A bonus: unlike the majority of ancestry-based tests, AncestryDNA's results are admissible in court proceedings as evidence of a sibling relationship.

Pros

• Ancestry's test offers dynamic, interesting results that are relevant to amateur genealogists, allowing for the identification of sibling relationships and much more
• Using the site connects your results to Ancestry's family tree builder and one of the largest collections of genealogical records available

Read our complete AncestryDNA review.

The Winners

• Best for legal relationship testing: BioGene, which is legally admissible in court proceedings without additional cost, is processed in only one business day, and allows you to submit a sample without first receiving a test kit if desired for your privacy.
• Best for peace of mind testing: AncestryDNA, which allows you to identify sibling relationships, interact with other living relatives, and see a breakdown of your ancestral ethnicity; subscribing also connects you to one of the web's most powerful family tree builders and a robust collection of genetic records that are ideal for helping you trace your roots without a struggle.

Neil Edwards

Genealogist and family-tree research specialist

Neil was born in Shropshire, England surrounded by centuries of living history. His interest in the past has been a lifelong passion leading to undergraduate degrees in both Economic History & Geography and History & Politics.

This interest in history quickly translated to family history when he moved to the U.S. in 2010. It was here that he began working on his own family tree as well as that of his American wife. That research allowed him to gain a wealth of experience working with both U.S. and European genealogical documents and studying their best uses in researching family history.

Following 9 years of honing his genealogical research skills, Neil was proud to have earned a certificate in Genealogical Research from Boston University in late 2019. Neil also took part in the research process for a Duke University study into the families of 19th Century UK Members of Parliament.

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