I have a 2 year old GSD (Arko) from working lines. He was doing well in Schutzhund, but my time has been very limited lately. I doo take him out almost daily (depending on weather) and run him, basic obedience. I have a wife and 6 year old son. Yesterday, while I was at work my wife and son decided to let Arko out of his run. She has done this many times. He comes out with tons of energy going after one of his toys. He's just happy to be out running out of the yard. According to my wife, she and Tommy (son) are standing on the opposite side of the yard when Arko runs at my son and body slams him. As he does this he continues to rip around the yard when my wife yells at him, scolding him. It was her perception that he was showin some level of aggression. Cindy (wife) proceeds to call Arko over to her and she grabs him by the scruff (no collar). Well, he doesn't like that and growls. She gets him into the house and into the crate and tries to be stern with him (although she's a bit nervous now) and tells him to lay down. He growls. Every time she says something, he growls. This dog has never shown any aggression toward anyone, least of all the family. Not having been there, I can only try to piece together what happened. I believe it was a dominance issue. I (alpha) was not home and he's trying to establish the pecking order. I am the only one who feeds him and does the training. Having said all that, my wife is nervous with him now and I think my son is but will not admit it. Advice, thoughts?