Personal Curiosity and Identity
For many twins, knowing whether they are truly identical or fraternal is a meaningful part of who they are, and a question they have wanted answered for years.
99.99%+ Accurate · Painless Cheek Swab · Results in 3-5 Days
Twin Zygosity DNA Test
A twin zygosity DNA test tells you for certain whether twins are identical (monozygotic) or fraternal (dizygotic). Identical twins share the same DNA, while fraternal twins share about half their DNA like any other siblings. TestMark DNA confirms the answer with a painless cheek swab from each twin, with 99.99%+ accuracy and confidential results in 3 to 5 business days.
Free consultation. No obligation. Speak with a real person now at (866) 702-7644.
AABB-Accredited Labs
99.99%+ Accuracy
Painless Cheek Swab
Results in 3-5 Days
Discreet
Certified Network
Results in 3-5 Days
Confidential
2,297+
Certified Collection Sites
50
States Covered
99.99%
Accurate Results
Why People Test Twin Zygosity
Many twins are simply told a guess at birth based on the placenta, which is not a reliable way to know. A DNA test settles the question for good. These are the most common reasons people test.
Medical Reasons
Identical twins share the same DNA, so they share genetic risk factors. Confirming zygosity helps a doctor make better screening and prevention decisions for both twins.
Organ or Tissue Donation
Identical twins are the ideal match for each other. Confirming zygosity in advance is valuable for any future organ, tissue, or bone marrow donation matching.
Settling a Family Debate
When relatives disagree about whether twins are identical or fraternal, a simple DNA test ends the debate with a definitive, scientific answer.
Get a definitive answer
Call and we will walk you through the process and set you up at a certified location near you.
Call for a Free Consultation - (866) 702-7644How it works
Call for a free consultation
Our team walks you through the right test, answers your questions, and confirms your nearest location.
(866) 702-7644Visit your local collection site
Each twin provides a painless cheek (buccal) swab at one of 2,297+ certified collection sites. It takes only a few seconds per person and works for twins of any age.
Get results in 3 to 5 business days
Receive your confidential results delivered securely. Over 99.99% accurate, private, and legally defensible.
Call for a free consultation
Our team walks you through the right test, answers your questions, and confirms your nearest location.
(866) 702-7644Visit your local collection site
Each twin provides a painless cheek (buccal) swab at one of 2,297+ certified collection sites. It takes only a few seconds per person and works for twins of any age.
Get results in 3 to 5 business days
Receive your confidential results delivered securely. Over 99.99% accurate, private, and legally defensible.
Pricing & Free Consultation
Twin zygosity testing is priced by the number of participants, with no hidden fees. There is no charge to call and ask questions, and we confirm your exact price before you book.
No Hidden Fees
We quote your full price up front during the free consultation. No surprises.
Free, No-Obligation Call
There is no charge to call, ask questions, or get pricing. You only pay if you decide to test.
Fast, Confidential Results
Results are delivered confidentially, typically within 3 to 5 business days.
Frequently Asked Questions
How does a twin zygosity DNA test work?
Each twin provides a painless cheek swab, and an AABB-accredited laboratory compares their DNA profiles marker by marker. If the profiles match at every marker tested, the twins are identical (monozygotic). If there are differences at any markers, the twins are fraternal (dizygotic).
How accurate is twin zygosity testing?
Twin zygosity testing is over 99.99% accurate. The laboratory analyzes many genetic markers, so the result is a definitive determination of whether the twins are identical or fraternal, not an estimate or a guess.
Can it tell for sure whether twins are identical or fraternal?
Yes. A DNA test is the only definitive way to know. Identical twins share the same DNA because they came from one fertilized egg, while fraternal twins came from two eggs and share about half their DNA like any siblings, so the test conclusively distinguishes the two.
What sample is used for the test?
The test uses a buccal swab, which is a painless cheek swab gently rubbed inside the inner cheek. It is non-invasive, takes only a few seconds, and provides the same accuracy as a blood sample.
Can twins of any age be tested?
Yes. Because the cheek swab is painless and non-invasive, twin zygosity testing can be performed at any age, from newborns to adults. Many parents test their twins as infants, while others test as adults.
How long do results take?
Results are typically ready within 3 to 5 business days after both twin samples arrive at the laboratory. Call (866) 702-7644 for a free consultation and we will give you exact pricing before you book.
Find out if your twins are identical or fraternal
Accurate, confidential, results in 3 to 5 business days.
Call for a Free Consultation - (866) 702-7644