Let's face it family trees aren't worth the paper they are drawn on. Very very few of us are actually descended from the supposed ancestors whose surnames we bear. At a guess I'd say it's highly unlikely that the true male line goes back to more than a great great grandfather. It's just the way human beings are. On the radio this morning I heard a pensioner who recently found out his biological father was in fact a family neighbour and not the man he called "Dad" for more than half a century. With no disrespect to any of the women in my family tree, I'd be surprised if I am related to several of my more distant male ancestors listed at the Scottish Records Office. But being more inclined to believe that nurture counts more than nature when it comes to how a person turns out, I don't think that really matters. And the biggest health worry based on DNA, that I know of, comes through the female line and that's way less prone to error when it comes to family trees.