Originally they were very hard to tell apart, but then their mother took a little chunk out of the boy's ear. That, and his face is a little less "fluffy" than the girl's...other than that, theyre pretty much identical.
Regarding keeping these fluffballs--It's crazy, cause I want people to buy them (once they're old enough, of course). (Me and my mom bred my chins to see if there is any interest for chinchillas in the area, because if there is, we might start breeding chins). And it's like I want them to sell so that we can start up the breeder business over here, but I want to keep them. They're just so adorable I want to keep them all. Course I figure if there is interest and we start breeding, then I would always get to play with the babies until they got old enough. I'd enjoy that.
But at the moment they're not old enough to sell (yay, for now) so that's good. I love coming home to the little furballs.