That is an urban legend like the Doberman's brain never stops growing and eventually drives them insane.
I used to have a red doberman. Loved him to bits and he was a TOTAL coward unless he smelled fear on you. THEN and only THEN would he "grow a pair." Bo snapped at me just once. When he did that - I opened his moth - stuck in my arm and told him - you wanna bite me - this is your chance. He spat out my arm and never once snapped at me again and I had him for years. I did knock him out once though . . . . YES I decked a dog - but that's another story . . . .
Stand up for what is right, even if you have to stand alone.