I finally made my dog's appointment after doing a lot of research, both online and talking to others in the performance world. The bottom line, from what I came up with anyway, was that waiting until they are two would ensure that my dog was fully grown and formed and the chance of decreased drive would be minimal. Why get him neutered at all? First, he doesn't need the distraction, but most importantly, the risk of testicular cancer increases the longer they are intact. That said, testicular cancer is pretty rare. Sam probably did not need to be neutered; he was practically asexual. But, he did get picked on a lot, which went away after his neuter. Linus, on the other hand, is all boy, and while he's not awful at all, there are some habits that are more annoying than anything, and they should decrease after his surgery.