Clone: The Road to dolly and the Path Ahead.

• Author: Bailey, Ronald

by Gina Kolata, New York: William Morrow & Co., 276 pages, $23.00

Cloning human cells could one day save your life and the lives of the people you love. Yet Congress seems hellbent on stopping the medical advances that cloning can make possible. Congress is responding to polls that show most Americans are opposed to the cloning of human beings. But carelessly crafted legislation would restrict not only research leading to the birth of cloned people but research that could find cures for cancer, genetic diseases such as cystic fibrosis, and damaged hearts, livers, and brains.

Now readers interested in this topic have two good, complementary introductions to the science, morality, politics, and future of animal and human cloning. Gina Kolata, who works for The New York Times, is one of the best science reporters in America. Lee Silver is a professor in the departments of molecular biology, ecology, and evolutionary biology and the program in neuroscience at Princeton University. Kolata does a particularly good job of describing the science that led up to Dolly, while Silver explores the futuristic medical and reproductive techniques that cloning makes possible.

In February 1997, the Roslin Institute in Scotland, an Obscure farm animal research facility, announced that it had succeeded in toning a sheep from an adult, differentiated cell. The cloned sheep, Dolly, made headlines around the world and launched a fierce debate over the potential uses for this new technology. The breakthrough showed for the first time that genetic information encoded in the DNA of an adult cell could be "reset" and made young again. Once reset, the cells with rejuvenated DNA could produce all of the cells needed to grow a complete organism. "[S]uperficially, it's a step toward immortality," explained Ronald James, whose company, PPL Therapeutics, paid for the cloning research. "And if you take a step toward immortality, everybody stops and takes notice."

Since Dolly, much has happened. President Clinton imposed a ban on federally funded cloning research, and Pope John Paul II declared that each human being has a "right to a unique human genome." UNESCO has issued a Universal Declaration on the Human Genome and Human Rights declaring, "Practices which are contrary to human dignity, such as reproductive cloning of human beings, shall not be permitted." The European Union has also adopted a ban.

In the United States, the National Bioethics Advisory Commission issued a report last June calling for federal legislation to ban human cloning for three to five years. "Freelance" physicist Richard Seed created a mini media firestorm in December when he said he was looking for investors to open a toning clinic. Congressional hearings have been held, and in February the U.S. Senate debated a bill that would ban cloning research on human embryos. Throughout it all, bioethicists have been offering grim warnings about the moral dangers of human cloning.

As Kolata shows, the science of cloning is fascinating. The achievement of Ian Wilmut and his colleagues at the Roslin Institute was the culmination of decades of research on eggs, embryos, and in vitro fertilization. The researchers inserted the nucleus of an adult udder cell into a sheep egg cell whose nucleus had been removed, a technique called "somatic cell nuclear transfer." Once the egg with its new nucleus began to divide, Wilmut implanted the developing embryo into the...