Cloning is among the more controversial topics of the day, and for good reason.

Serious ethical questions surround the practice of taking a piece of a living thing and creating a copy, especially when human beings are involved.

The emotional debate over whether to pursue and even fund cloning has pitted religious conservatives who object to people trying to play God against medical researchers hoping for scientific breakthroughs that save lives.

And even though most Americans polled maintain that they're uncomfortable with the practice of cloning animals, many companies in the United States and overseas have for years gone ahead with successful cloning of sheep, cattle, dogs, cats, mice and other creatures.

Animals are cloned for reasons ranging from the development of drugs to attempts at saving endangered species. Livestock have been cloned to produce breeding stock.

In one recent and noteworthy development, a South Korean biotech company cloned four puppies from a black Labrador retriever named Marine, who has the distinction of being considered one of the best cancer-sniffing dogs in Japan.

Man's best friend is known to have a remarkable sense of smell, such that some researchers are convinced dogs can sniff out chemicals diluted as low as parts per trillion.

Cancer cells are believed to give off a special odor, and recent studies have shown dogs making positive identifications of certain cancers in a remarkable number of cases by smelling the breath or skin of patients.

If that isn't amazing enough, now there's the notion of creating an army of dogs that could possibly be useful in the early detection of cancer cases.

Using dogs isn't a foolproof way to detect cancer, of course. But the study of dogs detecting cancer could lead to related scientific breakthroughs that improve the odds of discovering the disease while it's still treatable.

Meanwhile, no one can say for sure whether the Labrador retriever clones will have the famous canine Marine's purported ability to identify cancers.

But if it turns out that even one pup appears to possess such talent, the cloning would indeed be an acceptable step toward learning more about what could be done to save the lives of people stricken with cancer.