Non-paternity event

In genetics, a non-paternity event (also known as misattributed paternity, not parent expected, or NPE) is the situation in which someone who is presumed to be an individual's father is not in fact the biological father. This presumption of NPE is a subset of a misattributed parentage experience (MPE) which may be on the part of the individual, the parents, or the attending midwife, physician or nurse. An NPE may result from sperm donation, undisclosed adoption, heteropaternal superfecundation, promiscuity, paternity fraud, or sexual assault, as well as medical mistakes, for example, mixups during procedures such as in vitro fertilization and artificial insemination.^[1] Where there is uncertainty, the most reliable technique for establishing paternity is genetic testing; however, there is still a risk of error due to the potential for gene mutations or scoring errors.

Overall, the incidence of misattributed parentage experiences ranges from about 0.4% to 5.9%,^[2] though it may be higher in certain populations. The discovery of previously unsuspected or undisclosed non-paternity may have both social and medical consequences. Non-paternity that is due to a previously undisclosed extra-marital relationship often has serious consequences for a marital relationship. Non-paternity is medically relevant when interpreting the results and utility of genetic screening for hereditary illnesses.