I'm in the exact same position you're in, Emanuelle. I have a Boston, he's now 14 months old and I've resisted neutering him. I don't see any benefit to the male dog - whatsoever - in neutering them, but it does keep people from accidentally breeding. It also helps with "marking" the furniture in the house - which is a benefit to the owner.
My last BT was a female, and I would recommend spaying them after the first heat is over, because females are prone to cancer. They are also prone to urinary incontinence when spayed, which is a huge problem if you sleep with them, but apparently that can be handled with a medication that strengthens their ureter muscle that is weakened by the lack of female hormones.
My BT is a very very healthy trim little guy, never over eats, has plenty of energy, weighs about 20 pounds. I also have a lab beagle mix who was very healthy until he was neutered, now he's a big fat lazy lug of a dog who's constantly hungry. Interestingly, they eat about the same amount and the lab mix is fat and never seems to feel like he's gotten enough to eat. So I'm very disinclined to neuter my BT - except in the last month or so he's developing some unsettling dominance issues at the dog park where he picks on the weakest dogs. Not good.
Best wishes with your decision. The spay/neuter campaign is fueled by the overpopulation of dogs in the US, and those who can't keep dogs from breeding should ABSOLUTELY do that. Others have more time to consider health options for the dogs themselves, if they really and truly can keep litters from happening.
(I'm 52, have had dogs all my life, some male and some female, some neutered and some not, never ever been responsible for a litter).
I personally would never get a dog fixed under a year old, even longer if he were a large breed dog. I believe there is a huge benefit to giving the body a chance to mature the way nature intended and in giving harmones a chance to circulate through the body. There are many good articles on both sides. As far an cancer is concerned, I don't believe that whether you get your dog fixed a year earlier or later makes nearly as much difference as the kind of food he/ she eats and the vaccines they receive.
You may also want to do some research on dog vaccines and over vaccination.
When my doctor suggests I do something, I always go home and do a ton of my own research before deciding. I believe my pets deserve the same :)
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It would be best to neuter your dog when he is younger, most of the time pups heal faster and take less time to bounce back into the swing of things. I am not up-to-date about Boston Terrier cancers due to early neutering, but most dogs benefit from neutering. Cancers such as testicular cancer can not occur. It is also easier for the vet when the testicles have not formed as strong as a bond with the gubernaculum (aids in descent of gonads).