A Brief History of Paternity Testing

Before DNA testing became available, several blood-testing methods were used to determine paternity. These tests based on different blood group systems (BGS) were difficult to perform and often produced inconclusive results. Most courts now accept only DNA test results as evidence for paternity cases, and the overview below explains why.

1920s—Blood Typing
Power of Exclusion: 30%
Blood typing, based on the ABO blood group system, is not an accurate method for determining paternity. It eliminates (excludes) only 30% of the entire male population from being the possible father. It cannot be used to prove paternity.
1930s—Serological Testing
Power of Exclusion: 40%
Serological testing, a type of blood testing based on the Rh, Kell, and Duffy blood group systems, eliminates only 40% of the entire male population from being the possible father. Serum testing cannot be used to prove paternity.
1970s—HLA Typing
Power of Exclusion: 80%
It was only in the 1970s that a significantly higher power of exclusion was achieved for a paternity testing method. HLA testing eliminates 80% of the male population from being the possible father, and in some cases, it is possible to produce a probability of paternity of up to 90%. However, HLA testing cannot differentiate between related alleged fathers.
1980s—DNA Testing via RFLP
Power of Exclusion: 99.99% and higher
In the 1980s, DNA testing became available. DNA, the genetic material, is found in all cells of the body. You inherit a unique combination of DNA from your mother and father, and no two persons have the same DNA, except for identical twins. Thus, DNA can be used to conclusively determine paternity.
1990s—DNA Testing via PCR
Power of Exclusion: 99.99% and higher
The Polymerase Chain Reaction (PCR) became established in the 1990s as the standard method for paternity testing. Like RFLP, this method uses DNA, which is found in all cells of your body. You inherit a unique combination of DNA from your parents.
Because scientists have extensively used PCR for DNA testing, a greater amount of information has been accumulated to form a database for accurate DNA analysis. This large database enables paternity testing via PCR to have the highest power of exclusion.

DNA Testing via PCR is the fastest, most accurate method for determining paternity and establishing other relationships.