There are many situations where a grandparent needs to be tested against a grandchild when the father is not available. For example, if you want to find out but not raise the suspicion to the father, if the father is in another state, incarcerated, serving in military abroad, or if the father is deceased.
Often times, a grandparent will wonder if the child really was fathered by their son. This can be a sensitive subject and it sometimes is best to find out before approaching the father with the possibility. Other times, the father can just refuse to believe that there would be any way he could not be the biological father of the child. Many caring grandparents are in this situation. If you are, don't feel like you are alone, or like there are no options.
Advances in technology have made it possible and Paternity-USA makes it affordable to test DNA from one grandparent and one grandchild and determine the percentage of probability of a true biological relationship. It is best to include the child's mother in the test if she is available, however. Including the mother's DNA will totally eliminate all of her DNA from the child's profile, and the lab will be left with only the DNA that the father donated to the child, to compare it with his parent. This gives a higher level of conclusiveness. The testing can be performed without the inclusion of the mother if necessary though.
A common use for a Legal Grandparent DNA Test is to provide documentation for a child to receive Social Security benefits after the father has passed. In these cases, including the mother in the test is almost always a necessity. A legally binding document must be presented for the child to receive benefits if the father was not on the birth certificate. This type of DNA testing is an invaluable way to help ensure your grandchild will be provided for financially.
Another method of Grandparent DNA testing is to test BOTH paternal grandparents with the child. This is called a Missing Parent DNA Test. In Missing Parent Testing, essentially the two grandparents' DNA is combined to "recreate" the father's genetic profile. This profile would be then compared to the alleged grandchild and will generally produce a very conclusive DNA test result. In this test, as with the Grandparent test, it is beneficial to include the mother if she is available.
If any of these circumstances apply to you, and you want to find out once and for all... make sure you do business with a DNA testing lab that is AABB Accredited.