As the drive to pass along one’s bloodline and family name increases, so too does the unintended likelihood that many of the ancestors involved were adopted or the result of a union outside the official tree. AKA: The Macho Bloodline Conundrum.
Having worked with many family trees, I can say without hesitation that this is more likely to be the rule rather than the exception. Behavior and decisions were much more easily overlooked or concealed in the past; DNA has eliminated many of these variables, especially in the last 4 generations of family. Through the span of history, however, every family tree tends to have many dead limbs and invisible branches.