A legal twin zygosity DNA test from DDC can conclusively determine whether twin siblings are identical or fraternal twins. Twins and parents of twins often initiate this genetic test to satisfy their personal curiosity. Others initiate a legal twin zygosity DNA test as a safeguard for possible future medical emergencies—identical twins are perfect organ and tissue donors for one another.
Identical twins develop from a single zygote—the union of one egg cell and one sperm cell during conception. Because they come from a single zygote that splits during its early development, identical twins share the same DNA profile.
Fraternal twins develop from two zygotes—two egg cells that were fertilised by two sperm cells. Because they come from two zygotes, fraternal twins have different DNA profiles. Their profiles can be as different as any two non-twin siblings’ profiles can be.
By comparing the genetic profiles of twins, DDC can determine which type of twins they are.