Twin Zygosity Testing

Worldwide Genetics offers a unique DNA test to help twins and their families determine whether the twins are identical or fraternal. Called twin zygosity testing, this type of test is commonly used to satisfy personal curiosity. However, it can also be used to provide a critical piece of the twins’ medical history that can aid in the understanding, prevention, and treatment of possible inherited diseases.

The results of a twin zygosity test definitively show whether a set of twins is identical or fraternal. We achieve this result by examining and comparing the DNA profiles of the twins. (No individuals besides the twins themselves need to contribute DNA samples for a twin zygosity test.) Because they developed from one zygote (one egg and one sperm cell), identical twins have the same DNA profile. Fraternal twins, on the other hand, developed from two zygotes. Therefore, they have different DNA profiles; in fact, their profiles look like those of any two siblings.

You have two options when ordering a twin zygosity test: private testing (in which the twins collect their own DNA samples using our free kit) and legal testing (which follows the Chain of Custody process that makes the test results legally defensible). Our experienced customer service representatives are on hand to help you choose the best testing option for your needs.

Please call 1-800-DNA-8360 or use our online contact form if you have any questions about twin zygosity testing from Worldwide Genetics. We are happy to assist you!