This is what I have been posting to the participants in the NPE discussion on the DNA List. Non-paternity events----how often do they happen? Hi I have matches with my 4th cousin, 2 O'Briens and 20 some other surnames I have been working this issue for several months I can tell you that my matches have ruined one book, four paper trials and a couple of websites. The question should be how many paper trial are genetic correct. FanilytreeDNA used to state a rate of NPE at 5%. Then the legal and sales people thought that was a bad idea and we now have the big lie!!!!!(My speculation.) If paper trials are only 95% correct because of research error each genteration. What the error rate at 6 generations? Then add the NPE at 2%- 5% per genteration. Of course every Genealogist know that he 100% correct, it not good sales to put probability on that. DNA is needed to verify paper trials!! john b.