Hi James - let me put it this way - alcoholism is rife on my mothers side - but she rarely drinks.
Me my dad and my siblings have all beenn drinkers, My sister, like my mum drinks rarely, and my brother drank heavily as a young man but now, like my Dad always has been, he's well within the normal spectrum.
I was an alcoholic - but I stopped drinking.
Heredity may play a part in some cases - but it's no barrier at all to stopping drinking IMHO
D