The story of Dolly, the first sheep successfully cloned from adult DNA, is well known. In 1996 researchers at the Roslin Institute, in Edinburgh, Scotland created Dolly using cells from a six-year old ewe. Their work was published in 1997, activating a debate in the science community about the possible dangers of cloning.
One of the ongoing concerns is that Dolly displayed the symptoms of old age early in life and was euthenized at mid-life. Most sheep live to 11 or 12, and she was cloned from 6 year old genes. Was she "born" into mid-life?
The fact that arguments about this exist among knowledgeable scientists points out how little is understood about the effects of cloning. Those with commercial interests will listen to the arguments that best suit their needs.
We should want to know what effects there are to our various food products.
What are the dangers in having human transplant organs grown in pigs?
Will sheep modified with human DNA produce milk for safe treatment of human deseases? What will the effects be to the pure-bred pet market?
How will this effect horse racing? Will the tracks be populated with aging Barbero's? When Barbero was tragically injured, he was still worth a great deal of money as a stud. He didn't recover and was euthenized. The question of profit would look for viable answers.
What are your concerns about cloning?