Hi, I agree that one census can not determine ones true age, but the headstone is not much better. I have found that many of my ancestor's headstones give the wrong year of birth. I feel the best way to determine the closest true year of birth is to go with the census which was closest to the birth of the person you are researching. Along with that, find as many census's on that person and compare the ages. While I'd agree at times, neighbors may have given the census information on another family, I don't necessarily think it was the norm. Families were larger in previous years than now and people were not always as educated. Remembering the ages of 8 children, or trying to subtact from the present year, may have helped with the number of wrong ages found. This is why I feel that finding your ancestor, if possible, in his or her first 10 years, and going by that age, is the most likely correct one. As we also know, ladies especially were notorious for giving a younger age than was accurate as they aged over 15 years old, so again, an earlier census is preferrable. Since the same could be said as to the age they told their husband, or even their children in later years (if they told their age at all), and this is what age was likely shown in the year written on their headstone, so...I again feel, that if at all possible, find as many census's as you can on an individual, compare them and if they differ, go with the earliest census found. This is also why the ages on ones death certificate are not always correct either, and as for the state of birth for an individual and their parents, again, I'd go with the earliest census which shows that information, unless other data proves it later, to be incorrect. Christi