Prepared by Elisabeth Lindsay.
A non-paternal event is a term used in DNA research indicating a break in the Y chromosome line in which a man's legal surname and his DNA do not match the DNA associated with that surname. A non-paternal event can may occur for a variety of reasons: adoption, illegitimacy, a name change, a child carrying a mother's or step-father's surname. Or it may be that an error was made in the research somewhere along the way, resulting a person's DNA being compared to the same surname, but the wrong family line. it is also possible that the DNA test itself could be misleading, if the DNA sample size were too small to produce an accurate probable result.
The moral of the story is that we must always acknowledge the margin of error, in research and DNA testing. Non-paternal events can be discomforting and can even cause family discord. Before jumping to conclusions, it's always best to go back to the beginning and evaluate the research. It may also be important to keep in mind that a non-paternal event does not alter a person's identity, but only adds new information.