No he won't. He may be gentler with it because it's a puppy, but he won't know it is his progeny. I have to ask, If your dog is dog aggressive, or "not good with other dogs" why are you getting a second dog. It just seems unfair to both dogs involved to take a chance that there will be future issues in your home. While this dog is a puppy , it may be ok but as it gets older things can escalate. That said I do hope you are getting a female.