The ballyhoo that has greeted the recent work on cloning animals tends to focus on the possibility -- and fear -- of cloning human beings. But the real payoff of present work may be much less dramatic, and make much more difference in terms of health care. PNS associate editor Walter Truett Anderson, author of "Evolution Isn't What It Used To Be" (W.H. Freeman), is a political scientist who writes widely on technology and global governance.

After all the sound and fury about the cloning of human beings, the really stunning outcome of the recent genetic experiments may prove to be the cloning of individual organs -- replacement hearts or kidneys that would not be rejected by your body because they would be perfect copies of the original organ.

The possibility was immediately recognized by many scientists who heard the news about the famous experiment with Dolly the lamb, and the developments that have followed, including the recent cloning of mice by a team of scientists in Hawaii. But it has received almost no mention at all in the news media, despite an enormous volume of speculation on cloning and its ramifications.

It seems highly likely that the know-how now being developed by the cloning experimenters could eventually be applied to producing, not duplicate human beings, but perfect duplicate organs for living human beings -- a liver or a pancreas, for example, grown from the patient's own cells to replace one damaged by disease or accident.

The secret to such a technology would come from further understanding of what is sometimes called the "programming" of genes. As an organism develops from the fertilized egg, it creates various kinds of specialized cells. Each cell contains the individual's entire genome, but expresses only the genes necessary to shape it for its particular role in skin, blood, heart, or eye. As a metaphor for this, you might imagine a group of specialists in a factory, each performing one single task but each containing in his or her brain half-forgotten knowledge of how to perform every other task as well, including knowledge of how to create a new factory.

Until recently, the prevailing belief was that, once a cell had begun to specialize, it could never be "reprogrammed" to create a whole individual -- that the only cells capable of doing that were the embryo cells created by the fertilization of an egg (or, in a few cases, by an unfertilized egg). This is the assumption that Ian Wilmut of Scotland and, now, several scientists in other parts of the world, have thrown into the compost pile. Specialized cells are now being successfully reprogrammed to take on the work of directing the creation of a new sheep or mouse that is a duplicate of the animal from which the cell was taken.

The fascinating question that opens up now is whether this same knowledge can be applied to grow, instead of duplicate animals, duplicate organs. If it can, it will produce medical feats beyond anything ever seen in the infirmary of the Starship Enterprise.

Organ replacement is already a fast-growing field of medicine, part blessing and part tragedy. The blessing is that it has saved many lives and enabled many individuals to lead normal existences instead of being invalids. The tragedy is that the supply is so far short of the demand that many people die while waiting their turn, while families and public-health officials argue about which patients get to live, which get to wait. Poor people have scarcely any hope at all of receiving replacement organs, and many are now voluntarily selling their own organs -- usually kidneys -- as a way of earning money.

Despite amazing advances over the last few decades, even the best organ-transplant technology still leaves a lot to be desired, as the patient's body still often rejects the transplanted organ.

It's possible that better methods of preventing organ rejection may be developed, and it's also possible that animals such as pigs will become a major source of organs for transplantation into human beings. But the better methods aren't here yet, and the animal-to-humans prospect carries many problems including the fear that diseases may be carried into human bodies along with the transplanted organs.

Cloned organs are still a long way from reality, to be sure -- but such a development is still a plausible possibility that stands a good chance of being achieved in the next century. If it is, it will revolutionize medicine, extend human life spans, and probably make a profound difference to far more people than the human cloning now being endlessly and breathlessly discussed.