Genealogical research, like the grounds of reason, is a vertiginous abyss. There is no way to ever get to the 'root' or origin of a family 'tree' simply because there is no root. Putting aside the difficulty of matrilineal descent, the whole idea of the familial places stress on the necessity of order and while most families are decidedly disorderly, the concept of the familial is dependent on categorisation.

"If there is a characteristic of the suburban approach to forming knowledge out of information, it is, broadly speaking, an emphasis on rationalism. By this I mean a bias towards pre-formed categories into which new information is to be slotted, rather than a bias towards creating categories out of the new and unexpected patterns imminent in new information itself. Rationalism, understood in this broad sense, is a common feature of suburban thinking. It is what creates the suburban tendency to resist new information when it doesn't fit the assumed order of the world." (Wark quoted in Lucy, 2001, p.141)

But resisting the tendency to rely on pre-formed categories in genealogy is akin to trying to counter the speech/writing opposition by going 'beyond difference'. It's difficult to think of the family outside of the familial. We may all leave home but that doesn't mean we have escaped from the family. By its very nature, genealogy tries to do nothing less than ground our identity on the logic of our genes. But there is no ground and that shouldn't disturb us.

"'Feel it, our difference.' There is no regulating system of rules 'behind' culture, but only an asystematic flow of events across surfaces. 'That is it, all there is.' Our difference lies in the responsibilty to know that there is nothing outside the text, beyond culture or beyond semiotics." (Lucy, 2001, p.141)