Aggressive animals are made not born. There is no breed of dog that is born aggressive. Nurture, not nature is what turns an animal aggressive. Dogs may be born with personality disorders, as a result of bad breeding, or a birth defect that they will usually inherit from the mother. They are not born, possessive, aggressive or violent.
Puppyhood, and adolescence to dogs are toddler and teenage years to children. If you’re absent for them as a pet parent or parent, you have yourself to blame. Exhibit selfish or irresponsible behaviour and your pup or child will learn from you. Give them confidence through games and dog toys that teach them to share, and entertain them.