Your Bulldog is still a puppy, at 1 year old, and has already bitten your son... call a certified pet behaviorist right now! While it could have been an accident or a playful nip, it IS unacceptable. This website will help you find a certified behaviorist in your area: http://iaabc.org/ What you DO NOT want to do is contact a random, unaccredited, uneducated trainer. Anyone can call themselves a trainer, without truly understanding applied, scientific methods.

This is not about you "being the boss". It's about a dog who is growing up & sounds like he really lacks impulse control and fails to give proper warnings, which is common in Bulldogs. People believe the stereotype that Bulldogs are lazy, passive pets; but they were bred for hundreds of years for bull baiting and dog fighting, and their edge does come out from time to time. That doesn't mean you should counter his aggression with even more aggression; you're just going to get a ticking timebomb of a dog who fights you tooth and nail. What you want to do, and what a behaviorist will help you do, is lower his arousal levels, make your son and other dogs positives to him instead of threats, and generally teach him better self control and manners. Don't make him feel the need to guard, by feeding him separate from the other dogs, at least until you get professional advice on how to deal with guarding. It also sounds like he'd benefit from more intense, individual exercise and obedience training. Bulldogs are definitely bull-headed, they are super lovable, but they are not your average dog.

I would highly recommend neutering your dog! I'm fine with keeping dogs intact as long as they don't have behavioral issues. If they do, it's going to be worth it to neuter him, it's going to calm him down to not have testosterone pumping through him. Why would you want to breed a dog that shows aggressive behavior at only 1 year old? Behavior is passed down, and it's likely that he is from less-than-stellar lines to be displaying these traits. That does NOT make him a bad dog, that does not mean he isn't adorable or can't be a wonderful pet, it just means that it's not a good idea to breed poor examples of the breed. Bulldogs should be incredibly good-natured, Bulldog people have been improving the breed so much as far as temperament and it's not a good idea to breed anything less than an excellent example of the breed.