One of my ancestors was named John White. He was a very early settler of Ohio, marrying Priscilla Devol in 1790 when Ohio was still part of the Northwest Territory. Here is a timeline with some relevant (and undisputed) facts...
1758 : John is born on October 20 in Pomfret, Connecticut
1778-1780 : John served in the Revolutionary War.
1789? : John arrives in the Northwest Territory.
1790 : John marries Priscilla Devol in Marietta.
1791 : John and wife are living in Fort Frye Garrison.
1791 : Sophia White is born in Marietta.
It is interesting (to me at least) that there is a fundamental question about this reasonably well documented man. Who are his parents? If one listens to the wisdom of the internet, as exhibited by the good people of ancestry.com, his parents were a couple named Jacob White and Dinah Cutler. In fact, in the public trees where John and his parents appear, there is a single exception (which will be described quite soon) who does not list this couple as his parents.
The single exception is a tree I submitted that is based on the work Genealogical and Personal History of the Upper Monongahela Valley, Volume 3 by the professional historian, James Morton Callahan. In this book, we have the following snippet...

Further along it becomes quite clear that John (4) is the John White we are interested in. It mentioned his marriage to Priscilla Devol and Sophia being born. However the parents of John given here are John (3) and Unknown.
Normally, when faced with a choice between a professional and the internet, I'd go with the professional every time. Indeed, after digging a little further we get a little more insight. The Barbour Collection of Connecticut Town Birth Records (pre-1870) lists a John White being born in Pomfret to Jacob and Dinah, but on October 21, 1762, not October 20, 1758. Given that the 1758 is clearly legible on our John White's gravestone, and that John White is a common enough name that even a small town can have two of them born a few years apart, my guess is that the historian is right, but I'd like to hear other opinions on this.
Boiling this down to one question... Given all of the information posted, should I go with the professional or with the internet?
Update: Here's a summary of the facts I have.
The Barbour Collection contains a record of a John White being born to Jacob White and Dinah Cutler in Pomfret, CT on October 21, 1762.
The same collection contains no records of a John White being born in Pomfret on October 20, 1758. (Subquestion : How complete are these records for that time period? This is rhetorical and not meant to be answered here...)
John White was a Revolutionary Soldier. (Rhetorical subquestions: Would a teenager have been allowed to participate in the war? Could he have changed his stated birthday in order to join the army?)
John White had an "uncle" named Amos Grosvenor. The Barbour Collection has an Amos from Pomfret marrying a Mary Hutchins in 1755 (and no other marriages for said Amos). If he is really John's uncle, this would seem to eliminate the Jacob/Dinah possibility.
All in all, I think the best way to resolve this would be to investigate the Amos Grosvenor link more thoroughly.
https://genealogy.stackexchange.com/questions/5437/familial-terminology-in-colonial-america
– DaveBlackston Aug 17 '14 at 13:58