I had this pit I got as a puppy who hated every dog he met. Was about 5 months old when I brought him home and rt off the bat wanted to fight my cat gyp. I broke him off wanting to fight with her for the rest of his life that first day. Still hated other dogs and we eventually git him clipped at around a year. It didn't slow him down one bit, if he was given one inch he would get busy on another dog. I had him put down because of his dog aggression. He was great with kids and people and smart as hell but damn loved to fight. I really don't believe getting a male fixed will change him other than wanting to breed a bitch in heat.
If the dog you put down for being dog aggressive was an APBT, neutering it likely wouldn't have had much effect on the dog being dog agressive, as we all know the genetic make up of that breed in particular. I have seen neutering be very effective in many other breeds though, breeds that were not selectively bred specifically to be dog aggressive.
