I am as much the choices of my mother, father, grandmother, great-gradfather, etc. as I am the choices I have made. Everything they did led to my being were I am today. In Nature/Nurture terms, my nurture (environment/context of my life) was determined by them -- where I happened to be born and when, etc. -- as well as my biological make-up and the blessings and challenges that come with it. That IS genetics. And things within me, from them, are released: The process of growing older is perhaps a simple process of breaking down cell walls, releasing things that have for a while been bound up in the firmness of young muscle.
Like the tendency towards heart disease, stubbornness, even strong faith in God... It is handed down and ...how far back beyond one ought to go, and how infinitely much one could fill in to the bare outline of two generations!
To know myself I HAVE to know them... I think this is why I never regret the time spent listening to stories of ancestors, reading family histories, trying to understand my family.
To know what Harry Mason is, as of JAnuary 1931, I should have to know every thought, accident, rebuff, humiliation, triumph, emotion, that ever happened to him and all his ancestors, and beyond that I should have to with him against a set of standards to which I was willing to subscribe. That would be understanding but that kind of understanding can only happen instantaneously in the mind of God.
I can never know everything -- but I can know a lot. And I can be grateful for it.