Paternity and Twins
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.