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Twin Zygosity DNA Test

A Twin Zygosity DNA Test is a conclusive way to determine if twins are identical or fraternal. Identical twins come from the same egg and same sperm so their DNA is exactly the same and thus are their features. For identical twins, the DNA profiles are an exact match.

Are They Identical or Fraternal?

Knowing whether twins are identical or fraternal is often difficult. Appearance alone can be deceiving, since identical twins do not always look exactly the same, and fraternal twins often appear very similar. Twins sometimes grow up without knowing for sure whether they are identical or fraternal.

Can’t the Doctor Determine Twin Zygosity Before or During Birth?

Identical twins often form in a single sac, sharing a placenta and amniotic membranes. An ultrasound during pregnancy can reveal whether twins share a placenta. If each has its own placenta, they are usually fraternal twins. But some identical twins will have their own placentas, and some will share, depending on when the fertilized egg split. So how it looks on an ultrasound is not definitive.

You should consider a twin DNA test under any of the following circumstances:

  • If you are a parent of twins and want to know for sure if they are identical or fraternal.
  • If you have lost the birth records of your twins or you suspect that they are inaccurate.
  • If the placenta was damaged during birth
  • During treating high-risk medical conditions where twins’ organs or blood may be useful for treatment.
  • If parents question their twins’ original zygosity or if they observe that the twins are growing differently as they age.

The Zygosity Test is any time after the twins are born, as children or as adults. 

The DNA twin test is fast, simple and painless. A DNA sample is taken from each child by rubbing a painless cheek swab gently inside the child’s mouth. The samples are then tested in a laboratory and the DNA compared.

A twin zygosity DNA test determines if the twins or identical or fraternal. It cannot help in determining the physical traits such as hair color or skin color, thinking and attitude or other physical or mental characteristics of twins.

The test also cannot predict the probability of hereditary diseases in twins.

Yes. As long as the twin DNA test is done by an accredited and licensed lab, with all required consents from the legal guardians, and a chain of custody, the test results are very well valid in the court of law.

If the individuals to be tested live in different cities, or even different countries, each specimen can be collected individually and compared once the lab has them.  Please let us know this when ordering.

Identical twins have identical DNA

A Twin Zygosity DNA Test is a conclusive way to determine if twins are identical or fraternal. Identical twins come from the same egg and same sperm so their DNA is exactly the same and thus are their features. For identical twins, the DNA profiles are an exact match. Fraternal twins result from two separate eggs that are fertilized by two separate sperm. Though fraternal twins have some similarities, and are siblings, they do not share identical DNA. This test is very useful for parents who are keen on knowing the features of their twins and to serve as a valid legal proof regarding the identity of twins.

Other DNA Tests Available From InOut Labs