Twins DNA Test

Use DNA to understand the relationship between twins.

How Do We Know for Sure if We’re Identical or Fraternal Twins?

Only twin zygosity DNA testing can positively confirm whether twins are identical or fraternal. Although more than 70% of Dichorionic Diamniotic (Di/Di) twins are fraternal, they can also be identical. A twin zygosity analysis compares the twins’ DNA profiles to see whether they match—an exact match proves they are identical. Twins of any age can be tested. The report is posted to your secure online account just 2 business days after all samples have been received at the lab. Contact our experts today for a free consultation.

The DDC Promise

Results in 2 Business Days

once all samples arrive at the lab.

PhD-Reviewed Results

Our in-house team ensures accuracy.

Team Support

We keep you informed every step of the way.

If you are adult twins living in different states, we’ll send out separate testing materials—easy!

Reasons to get a Twin DNA Test

  • To confirm the truth about a twin relationship
  • Medical and/or health reasons
  • Lost medical records about zygosity
  • To put to rest doubt that may have arisen because of the twins’ physical characteristics as they age

Results are completely confidential, and your private genetic information is never shared with or sold to outside parties. See our privacy policy here.

Testing Options for Twin DNA Testing

Legal: If you want names of the twins on their DNA-test report, choose the legal option with witnessed DNA-collection. DDC coordinates DNA-sample collection at an approved location near you. These results are court-admissible.

Personal Knowledge: If you need the sibling-test results solely for peace of mind and are not concerned with having the twins’ names on the report, you can collect your DNA at home and send it to DDC for testing. Keep in mind results are not court-admissible.

TIP: If you think you may need results for court in the future, we suggest you do a legal test in the first place so you only have to test once.

To order a Twin DNA Test, call 1.800.681.7162

More about this Test

Q: My twins had separate placentas. Doesn’t that mean they’re fraternal?
A: Twins with separate placentas are not always fraternal. Only a twin zygosity DNA test can confirm the exact relationship between twins.

Before the widespread use of DNA testing, medical professionals (and therefore parents) assumed that, if twins had their own amniotic sacs and their own placentas, then they must be fraternal.

Fraternal twins come from two eggs being fertilized by two sperm. The zygotes implant separately, have their own in-utero “condos,” and can be girl/girl, boy/boy, or boy/girl.

Identical twins come from a single fertilized egg that splits in two. This division happens usually around days 4 or 5, and after the placenta and amniotic sac have started developing.

BUT :

If the fertilized egg splits before the placenta and amniotic sac normally start forming for identical twins, say around days 2 or 3, then each zygote develops its own sac and placenta.

So what could look like fraternal twins to medical pros is actually a set of identical twins!

Learn more

Q: Can results from a twin DNA test be used for legal reasons?
A: Results from a twin DNA test can be used for legal reasons if a chain-of-custody process is followed: the test is set up by a DDC specialist, DNA-collection is witnessed at an approved facility, and samples are sent directly to our lab for testing from the facility. If you just want answers for personal knowledge or as a guide for possible future medical treatment, then a home twin DNA test is an option.
Q: Is there a minimum or maximum age limit for a twin DNA test?
A: No, there is no minimum or maximum age limit for a twin DNA test. Testing is routinely performed for newborn, toddler, teen, and adult twins.