How exact is a DNA paternity test?

DNA paternity tests are the most modern and exact method used to analyse parentage. There are essentially only two results:

• "Paternity is excluded."

This means that the man tested is not the father of the child tested in this case (probability is 100%).

• "Paternity cannot be excluded."

In the case of non-exclusion, the exact probability of paternity must be determined on a case-by-case basis. The actual probability normally lies over 99.9% when, as in our lab, 16 independent systems are analysed. The probability is higher when a sample from the mother is included in the analysis (>99.999%).