Sometimes, a paternity testing question involves two alleged fathers who are identical twins. Can you determine the paternity of the child using identical twins? No. You can exclude and determine non-paternity but you cannot include them.
Twins have the same DNA and therefore, if they are alleged to be the father of a child, the results can only determine that neither twin is the father of the child in question or that one of the twins could be the father but it would not be possible through DNA testing to determine which twin is the father.
Do identical twins have different sets of fingerprints? The answer is yes and fingerprints are the best way to tell them apart. Fraternal twins on the other hand, have different DNA and different fingerprints so you can easily determine the parentage of a child if the twins are fraternal. A testing laboratory should always be notified prior to conducting a test if twins are being tested. In the case of identical twins, including one twin means including another, even if the second twin was not tested.
With fraternal twins, it is advisable but not necessary to test the second twin even if both were with the mother sexually within the same conception timeframe. If the second fraternal twin is not available for testing then the laboratory may opt to run additional testing if the need arises.