I think it's a very deep and great question. I'm sure there are studies out there, but who really knows?
We learn at a young age to do what is taught us. We also have the ability to overcome it.
Some of us will go the complete opposite.
Some of us will fall in line with what we learned.
My father is not an alcoholic but he drank when I was very young I witnessed the outcome of his drinking.
My brother on the other hand drank himself to death. (him being the oldest child)
My step grandfather on my fathers side WAS an alcohlic and I grew up with that.
My mothers family was totaly opposite and so I had both worlds or both genetics you could say.
Who Knows...who really knows? In the end WE have to make decisions for ourselves,but it is a very interesting subject in my opinion.