Both my wife and I quit drinking 7-8 years ago. This is rather ironic since when we met, she was managing a bar and was the head bartender.
My family has a real problem with alcohol, in that it was always the central point of any family get-together. Get together and drink. Go for dinner and get plastered. Even before I quit drinking I was really tired of that mentality.
With our son, we introduced him to alcohol at home and early (much easier to do in Europe). So by the time he was a mid-teen he'd already tried plenty of drinks (my wife can still mix a mean cocktail - and now mocktails). There was no thrill for him, and VERY importantly, he was not rebelling against his parents if he went out drinking, because he could have a beer or a glass of wine at home if he wanted.
Our son is now in his mid-20s and still drinks, but very responsibly. I think the amount of information available to young people in the last 15 years about the dangers of alcohol makes a huge difference compared to the last (my) generation.