Aggressive behavior towards men

Question
I have a 2 year old male boxer.  Over the past 8 months, I have noticed his increased aggressive behavior toward human males.  He will attack the fence when our neighbor is outside and he will not respond when I tell him to stop.  It's almost as if he's in another world and is unable to hear or maybe he just refuses to listen.  Our previous vet suggested to neuter him to calm the aggression, but I don't see any guarantee in that procedure.  My husband and I also have a female white American bulldog that's as calm as a lamb.  They were both brought into our home only a month apart in age.  We got them when they were both 2 months.  I cannot understand the behavior and I cannot afford for him to bite our neighbor(s). This behavior is not with all men, but with most.  When my father comes to visit, he does not get aggressive, we just isolate him from my dad during the visit, but he still shows no sign of aggression.  As an added precaution, we put him on his leash to slowly begin the integration process between him and my dad, but we still place him behind the barrier during the visit and listen to him whine.  When my grandmother comes to visit, he is not aggressive in any way.  We live in New York and dog training is extremely expensive.  What can be done about this behavior?

Answer
Honestly, I'd cut some corners and get the money together for a good trainer. It's still a whole lot cheaper than a lawsuit. Training will be useful to strengthen the relationship, and good management so he doesn't have the opportunities to rehearse aggressive behavior at the fence. You also want to be certain that he's not left out alone when he can be teased. He needs to know that you are able to handle situations, and it's not his choice to do so. You also need to teach him a rock solid recall and "leave-it" in situations where he's not so over threshhold he can't listen or respond, and I suspect you really need professional help to get these things accomplished. Sandy Case BFA MEd CPDT www.positivelycanine.com