What is it and when is it done: Identity testing is a method used to determine the genetic relationship between individuals or even different cells from the same person. It is most often used to establish the identity of a person's biological father, a process known as paternity testing. It may be done for legal identification purposes (paternity issues, crime scene investigations), twin zygosity (identical versus fraternal), and bone marrow engraftment (percentage of cells which are from the donor).
