Why, people want to know, did Barbra Streisand decide to clone Samantha, her coton de tulear? What would compel someone to spend $50,000 or more to create a genetic replica of a pet dog?

In the recent buzz over pet cloning, the issue has largely been framed as a personal decision, albeit a quirky one. But the decision to clone is not merely personal. There are broader ramifications for dogs, not only for the large group of dogs we call pets but also for a whole canine underclass that remains largely invisible to us but whose bodies serve as a biological substrate for cloning research and industry.

Clones like Ms. Streisand’s dogs Miss Violet and Miss Scarlett don’t materialize out of thin air but require the help of a whole team of female dogs. The cloning process begins with a group of dogs that will “donate” their eggs, a process that involves pharmaceutical manipulation of hormone levels and a surgical egg-harvesting procedure. Once removed from the donor dogs’ ovaries, the eggs will be enucleated — the unwanted DNA from the egg donor is wiped clean and the desired DNA from the pet is inserted.

If all goes well and the eggs fertilize, they will be surgically implanted into one or more canine surrogate mothers that will carry a litter of cloned puppies to term. After performing their tasks of producing a dog, the worker dogs will be used for another purpose.