Pure bred

I worked at a small animal clinic for a while. We had a gentleman that would bring in his German Shepard / Rottweiler mix for all his medical needs. He refused to neuter the dog though. We would discuss the pros and cons to neutering the animal to no avail. This went on for years. Finally one day someone asked why he wouldn't neuter the dog. We usually get the response that the people are afraid that the dog's masculinity will be removed or that it will change the dog's personality. Not this time. His response was, "My dog is very valuable. He is part German Shepard and part Rottweiler. He can father both purebred German Shepard and purebred Rottweiler puppies. Why would I neuter a dog that could make me so much money?" Nobody had much to say to that.