Gregg Miller says he's well aware that his business selling testicular implants for dogs invites just as many jokes as it does clients. That's because Miller's job is creating artificial dog testicles for canines that have been neutered.

"Dogs aren't stupid," he tells Business Week. "They would know if their eye was gouged out, or their foot was cut off. Why wouldn't they know if their testicles are now missing?"

But laugh all you want, Miller, 59, says his business has become a big success. He says 517,223 dogs in all 50 U.S. states and 49 countries are now wearing "Neuticles" manufactured by his company. Though, as Business Week notes, even Miller can't avoid slipping into unintentional humor when discussing his unusual business.

"When Neuticles were introduced commercially in 1995," he says, "people thought I was nuts," he said.

But as the comedian Joan Rivers asked Miller, "What do they do?"

Miller claims the Neuticles gives dogs a sense of restored pride. Though he recommends the "very lifelike" (and more expensive) silicone version of his product (up to $600) compared to the "easily detected" though more affordable "rigid polypropylene version (about $150).

"Generally pet owners think (Neuticles) are genius and non-pet owners think we're insane," he says.

And while Miller offers several different styles and sizes, he also requires customers to include information about their dog's age, weight and breed before matching them with the right pair. "Going larger can create short- and long-term complications and discomfort for the pet," he said.

More popular Yahoo! News stories

• Man uses kebab sandwich to 'plug' his own slashed throat

• Obama picture with student at Colorado bar goes viral

• White House party crasher Tareq Salahi running for Virginia governor