I've got 2 girls, 5yo and 3yo.
They know that brewing is my hobby, and know that much of my spare time goes into it. when the 5yo was learning to write a year or so ago she even wanted to write out instructions for me:
(add yeast does come after cool, she just ran out of room!)
She's fascinated by the process and how much is involved, and I think that curiosity in watching me make something is great.
But I rarely drink around them (can hardly appreciate it with all that noise!!), they never see me drunk and they are learning early on it's something to be treated with care. (the know that if dad's going to a brewers meeting or going out to see friends he can't drive home).
Like others have expressed here I figure it's better for them to see that beer is something to be appreciated, not just for getting wasted, and seeing what goes into it helps that. It's the same as when their mother bakes with them, they understand there's more to food than picking it up off the shelf.
I have this hope that by the time they're drinking age, they'll understand that alcohol is about flavour over intoxication, and will see kids that drink to get wasted as immature... (And that if either of them try to bring a mega-swill drinking boy home, he's going to cop the full craft-beer lecture!!)