What is the best breed of dog for a 13 year old boy?

A pug

Do you want it to live mainly inside, or be an outdoor dog? What is motivating your son to want a dog? Are you more interested in large breeds or small breeds? Are there particular skills you want the dog to learn (hunting, swimming, retrieving, etc.)?

as @juwhite1 suggests, it would be best to really consider what you are looking for in a dog and do the research to find the breed that best matches your desires. selecting the wrong dog is profoundly bad for both human and animal. perhaps talk to your vet about how to make the best choice not just for your son, but your family as well, good luck, the right dog will be a wonderful additions to the family!

Providing your son is responsible with and around dogs and is aware that he will have to train the dog and work with the dog in order to get the best results I would recommend the following breeds (obviously this is just down to my own experiences with dogs and children/teenagers. Every family, child and dog is different so it really all depends on your circumstances and for that reason what @juwhite1 and @avalmez said is obviously very important):

Jack Russell Terrier
Labradors/Retrievers
Staffordshire Bull Terriers (a breed that I have a LOT of trust in providing they are raised with a firm but loving hand)
West Highland White Terrier
Mixed Breed/Mongrel
Newfoundand or Bernese Mountain dog

I don’t know the name but it’s that kind of dog from the “Old Yeller” movie. Gift the dog along with a DVD of Old Yeller and Marly and Me.

@hungryhungryhortence a yellow lab i think..a good and patient breed all around. i esp like soft coated wheatens but like bull terriers they require a strong master. nonetheless, a great dog with loads of character (and, they are hypo-allergenic to boot)

Sheltie

To me, it is like saying should I get a brother or a sister for my son. I personally don’t believe you get a dog for a child, you get a dog because Mom wants to take on a 10–15 year responsibility. I loved my dog immeasurably but when I went off to college and then on my own, it was my mom who took care of my dog. So unless you are committed to having what is not unlike another child, don’t do it.

Now if indeed you are in favor of the addition, then I always have 2 suggestions.

If you are leaning towards a pure bred dog where you will know almost exactly how large it will grow to be, what its temperament will be, then go to a dog show. Look at all the different breeds and when you see one you like, wait until the handler is finished showing and then ask them if they have time to talk about the breed, or ask them for a card so you may call them later. They will tell you the good and bad about their breed.
Buy a catalogue, it will have a list of all the breeders of the dogs shown.

If you are interested in a mixed breed, then go to the pound and look into the eyes of the dogs until you feel a connection, and I say you, not your son, because it is going to be your dog, and then hope for the best.

Consider whether you want a dog that has to be professionally groomed. Curly coated dogs do not shed much because they matt instead, short haired dogs shed a lot, even if they are brushed.

I personally like corgis for pets, they are rough enough to run and tumble, smart enough to train, sometimes can be a bit nippy because they are herders, but can be trained out of that. Dogs from the working or herding group are always my choice because of their innate intelligency. Sporting dogs are next because they are loving and loveable, terriers and toys and the rest go downhill for me, but it is a matter of taste and what you want from the dog.

Good luck.