a fairly tongue-in-cheek
way of describing the pattern of familial line reincarnation
. the concept of familial line reincarnation
is fairly widely recognised
among most branches of paganism
the idea is that we continue to reincarnate to learn a certain set of lessons (sometimes one at a time, sometimes some in a group all at once.) but in general, there will be one or two major lessons to be learned in a life. and if you fail to learn that lesson, you get to do it all over again, and keep ending up in similar contexts until you finally get that lesson right.
this is where 'familial line' enters the picture. it is very very common (but by no means a given) that during the duration of trying to learn a given lesson, a person will continue to be reborn within the same bloodline. Of course it's not very common for the title, "i'm my own grandpa" to *actually* be fulfilled, but it happens occasionally. however, it is much much more common for people to end up as more distant members of said bloodline rather than the straight paternal male-to-male heir line.
almost always, after the lesson is finally completed, the soul will cease to be born in this family line, and enter a completely different bloodline, where they will stay for the duration of that lesson, and then again move on.