A paternity test is used to establish a biological relationship between a child and a father. Paternity tests are often tested as a “Duo” or “Trio” test. A duo test involves the child and an alleged father, while a trio test involved the mother, child and alleged father. At least 99.96% for Inclusive or 100% for exclusive.
When taking a paternity test, it is always important to state whether or not there is a possibility that there are potential fathers who are related (i.e. the alleged fathers are brothers, father and son, cousins, etc.) If this is the case, all related alleged fathers should be tested. Alleged fathers who are related have similar DNA, which could result in either an inconclusive result or a false inclusion.
For the majority of paternity cases, the 16 genetic marker panel is more than adequate. However, special circumstances can require extended testing to obtain a statistically desirable result.
DNA test results often decide the outcome of a paternity test. Paternity test results and conclusions are founded in statistics and probabilities. The greater the number of genetic markers examined the greater the strength of the genetic evidence and hence the final result. Enough genetic markers must be analyzed in relationship testing to routinely yield a combined paternity index (CPI) of at least 100. The industry standard is 16 genetic markers, however the use of fewer markers can yield accurate results. The 16 marker technology can achieve a probability of identity of 1 in 40 quintillion, or 1 in 40,000,000,000,000,000,000.
While a paternity test can performed without the mother, we recommend including the mother be tested in the event that the alleged fathers are related. Including the mother’s sample doesn’t just act as a quality and control step, ensuring the proper child has been sampled, but it also raises the validity of the test.
Not including the mother’s sample in the test reduces the ability to detect false inclusions. A false inclusion means an alleged father is tested and is falsely included as the father when he should really be excluded. When the mother is included in the test, the maternal alleles in the child can be accounted for, therefore narrowing down the number of alleles to be examined for paternity by 50%. When the mother is not included in the test, the father’s alleles in the child cannot be determined, therefore the father’s alleles have to be compared to every allele the child has. This decreases the paternity index at each marker and decreases the overall combined paternity index.
An additional reason to include the mother in the test is in regards to legal consent for the child. In New York State, if the alleged father is not on the birth certificate, he does not have the legal authority to sign for the child being tested. If the mother is involved in the testing she can provide the child’s birth certificate and gibe consent for the child to be sampled.