I'll second that. My baby brother almost got mauled a few years ago by a dog that hated anything male, just because the poor little guy was standing in the same yard -- if the dog's leash hadn't been just short enough, it would have seriously injured or killed him.

Even so, it was very traumatic and he only recently got over the bulk of his phobia about dogs, thanks to a friendly mastiff that lives near us. Unsurprisingly, the dog had to be put down. They couldn't rehabilitate it.