I'm not really worried about my son genetically being pre-disposed to alcohol in particular. Enviromentally yes, if his dad continues to drink. In my family, out of 20 people on both my mom and dad's side, there are only 3 who are alcoholics. On dad's side, he and his brother are addicted but neither of his parent's were. My moms, my grandpa was highly addicted but only one of my uncles picked it up.
However, that being said I do believe that there are alot of undiagnosed mental illnesses on both sides. Everything from depression, anxiety, bi-polar problems, OCD ect. I worry about him getting hit with something like that and that being a factor in why he may start drinking to start with. I'll definitely be watching for things like that and if they come up, I'll be getting him treatment pronto.