Tracing ancestry (was: Naughty, Guilty! DD)

[potioncat]

SSSusan wrote:
  WHY would this comment of Hermione's be true?  If 
> the generational span of yer average witchorwizard is 2 to 3 times 
that  of a human, wouldn't it be *easier* to trace the family tree? 

Potioncat:
But, so far, it looks like Wizarding youth mature and marry at the 
same pace, or even faster, than RL people! So if a new generation 
showed up every 20--25 years, you'd have the same number of 
generations to go back, just you'd have more of those generations 
still alive.

For someone from the Black family, it would be pretty easy...unless a 
direct ancestor had been blasted off the tapestry. But for a family 
that didn't keep records, it would be still be difficult. Wouldn't 
it? And even those who do keep records, many only trace the ancestor 
through the male line.

We have a cousin who is convinced our family is from William the 
Conqueror...Will's son, you know. 

Potioncat