DNA Testing Services » Twin Zygosity
A twin zygosity test is a DNA test that definitively shows whether twins are identical or fraternal. DNA testing is recommended by scientists for determining the relationship between twins.
Identical twins form from a single fertilized egg that splits into two genetically identical parts. Fraternal twins originate as two separate eggs that are fertilized and implant in the uterus.
The results of a twin zygosity test may be used to satisfy personal curiosity or to help solve health problems for the twins down the road. For example, in the event that a twin needs an organ or tissue transplant donor, the identical twin is a perfect choice.
There are also cases in which medical records regarding zygosity have been lost, or doubts may arise because of the twins' physical characteristics as they grow up.
In such cases, only a DNA test will be able to reveal the truth with 99.99% accuracy.