The genetic fallacy (also known as the fallacy of origins or fallacy of virtue) is a fallacy of irrelevance in which arguments or information are dismissed or validated based solely on their source of origin rather than their content. In other words, a claim is ignored or given credibility based on its source rather than the claim itself.
The fallacy therefore fails to assess the claim on its merit. The first criterion of a good argument is that the premises must have bearing on the truth or falsity of the claim in question. Genetic accounts of an issue may be true, and they may help illuminate the reasons why the issue has assumed its present form, but they are not conclusive in determining its merits.
In The Oxford Companion to Philosophy (1995) it is asserted that the term originated in Morris Raphael Cohen and Ernest Nagel's book Logic and Scientific Method  (1934). However, in a book review published in The Nation in 1926, Mortimer J. Adler complained that The Story of Philosophy by Will Durant was guilty throughout of "the fallacy of genetic interpretation." Adler characterized the genetic fallacy generally as "the substitution of psychology for logic."
From Attacking Faulty Reasoning by T. Edward Damer, Third Edition p. 36:
You're not going to wear a wedding ring, are you? Don't you know that the wedding ring originally symbolized ankle chains worn by women to prevent them from running away from their husbands? I would not have thought you would be a party to such a sexist practice.
There are numerous motives explaining why people choose to wear wedding rings, but it would be a fallacy to presume those who continue the tradition are promoting sexism.
Another example would be from How to Win Every Argument: The Use and Abuse of Logic (2006) by Madsen Pirie, p. 82:
The objections of the Council's new bus timetable come only from private property developers, and can be ignored.
As the author points out, private developers may well have legitimate and knowledgeable opinions on such a matter.