Parentage Test – A parentage test is a biological test performed to determine whether a person (male or female) is or is not the biological parent of a child.

Paternal – Related through one’s father.

Paternity Index – This value equals the odds that the alleged father is the biological father rather than any other man selected at random from the population.

Paternity Test – A biological test performed to determine whether a man is or is not the biological father of a child.

Pathology sample – A biological sample taken to study the presence and/or progression of a disease, such as cancer. It is often a tissue sample.

Patrilineal – Relating to descent through the paternal line.

Phenotype – The visible form of a genotype. There may be more than one genotype that presents itself as the same phenotype.

Population Database – A statistically significant set of data comprised of allele combinations for randomly selected individuals. Population databases are used to determine the variety and frequency of alleles at a specific locus in that specific population. They are used in paternity testing to calculate the Combined Paternity Index leading to the Probability of Paternity.

Postmortem – Postmortem means after death. It can also refer to the examination of a deceased individual to determine the cause of death and will often lead to the collection of several biological samples from the deceased.

Power of Exclusion – The ability of a genetic marker system to properly exclude a man that has been falsely accused of paternity.

Prenatal – In the context of paternity testing, a prenatal test is one that is conducted before the birth of a child, using an amniotic fluid sample or piece of the placenta (CVS), from the fetus.

Prior Probability (of Paternity) - The prior probability is a number anywhere from zero to one, that is assigned as the chance of a certain man being the father of a child, without any DNA testing. In a paternity test, the standard Prior Probability is 0.50 which is 50%. That means that, without testing any of the parties, there is a 50% chance that any untested man is the father and a 50% chance that he is not the father (i.e. same chance as flipping a coin). The Probability of Paternity obtained as a result of an actual DNA test can be compared to this Prior Probability.

Putative Father – The man who may be the biological father of a child.