It is NOT the breed. I think a bunch of fish breeders have just invaded the dog site. Poor breeding may be one cause. More likely, the early neutering has created a "fear based" aggression. The more success he has, the more aggressive he gets. Being aggressive toward other dogs and small children is easy...and gets the response he's after. "I bark, snarl, etc....they go away". Every time he succeeds at this, he will feel more successful and become more aggressive. What he needs is a good "butt whoopin". Neutering young is always a mistake...and the resulting behavior is often misinterpreted by young, inexperienced trainers. Looking to Yahoo is for the most part, pointless. Go get a trainer. Don't use any "Franchise" or "Chain" trainer....get someone that has had their hands on a few thousand dogs. No amount of book reading, videos, classes, etc. are gonna teach anyone squat. This is VERY common in working dogs that are neutered young. The thought is to prevent dominance, and what is created is fear (not always...but VERY often). A dog with weak nerves is dangerous. Do not let him have success with this behavior.