@MC: Welcome back!
@SM: Yeahhhh... I've played both games probably 500 hours each, and there is a LOT of blood. It's pretty cartoony and deliberately sorta dark-funny gore (the devs said that was intended), but I wouldn't suggest playing it in front of kids, though. When you go into VATS mode, it pauses the game and highlights different areas of an enemy's body, usually blowing the
everloving crap out of them.

VATS Mode
http://images2.wikia.nocookie.net/__cb2 ... er-SMG.jpgResult of VATS Mode
http://cdn.steampowered.com/v/gfx/apps/ ... 1343156749Shotgun blast in-game
In other areas to make you feel better, there aren't a whole lot of cuss words (da** and He** are in sometimes, but not many stronger ones), and no actual *birds and bees* (references though) and nudity, so you shouldn't have a problem there. They're a survival horror series, so expect scary stuff, that's pretty much it. The games are also hysterically funny and clever.
A LOT of games have a no-gore option (CoD, AC, etc), but Fallout doesn't. I personally love it for the horror aspect and handle mature things well, but I can easily see why some people would find it objectionable. In short, if you wouldn't watch American Psycho or Friday the 13th in front of your Mom/Dad, don't play the game in front of them.
EDIT: If you just are craving to play a Bethesda game while you're with your family, there's always Skyrim. Not much blood, no dismemberment, and literally NO cussing.