I have heard many times (including on this site) that you do not need to do any direct arm work to develop huge arms. Here are a few photos of the guys (Drew Baye and Martin Berkhan) who claim that they do not do direct arm or ab work - i.e., no standing barbell curls, for example. And yet they have pretty good arms.
Assuming these guys are not genetic freaks, I do not believe it. Do you? How would something like this work? I mean, why would anyone have huge quads, for example, by doing, say, shrugs? Similarly, why would anyone have huge arms by doing squats, deadlifts and rows?