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.  More specifically, it is a paternity or maternity test. 

Paternal – Related through one’s father.

Paternity Index – This value equals the odds, at a specific locus, that the alleged father is the biological father rather than any other man selected at random from the population. When individual paternity indices are multiplied together, this is called a Combined Paternity Index.

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 DNA 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.