When a team of South Korean scientists announced in February that they had successfully derived stem cells from a cloned human embryo, they trumpeted the potential someday to treat disorders from diabetes to spinal cord injuries. They also touched off the most serious moral and ethical debate so far over both embryonic stem cell research and human cloning.
The group, led by Hwang Woo Suk at Seoul National University, cloned human embryos using somatic cell nuclear transfer, a process that biologists have used to clone live animals. Their achievement marked the first time a cloned human embryo developed beyond a few cell divisions and the first time human stem cells had been derived in the process. In somatic cell transfer, the nucleus of an egg is replaced with the nucleus from another cell that contains the full genetic information of an individual. Then the cloned cell is induced to begin dividing. Only a quarter of the embryos Hwang cloned developed into blastocysts—hollow balls of roughly 100 cells. Just one yielded a self-reproducing stem cell line.
Almost immediately, groups ranging from the President’s Council on Bioethics to the U.S. Conference of Catholic Bishops assailed Hwang’s work, either because cloned embryos were destroyed in the process or because his research could lead to cloning humans. “Today cloned blastocysts for research, tomorrow cloned blastocysts for baby making,” said Leon Kass, chairman of the President’s Council on Bioethics, in The New York Times. Despite the controversy and the possibility of a worldwide ban on human cloning by the United Nations, scientists in the United States and Britain are already moving forward with attempts to repeat the process.
The cloning question became a debate within a debate. Stem cells themselves were a major issue in the 2004 presidential election, especially after the deaths of former president Ronald Reagan and the actor Christopher Reeve. Best known for his Superman films, Reeve had long advocated research into embryonic stem cells to repair the kind of spinal cord injury that left him paralyzed from the neck down after a horseback riding accident 10 years ago.
More surprising was the public position of members of Reagan’s family—his widow, Nancy, and son Ron—against the Republican Party and its standard-bearer, President George W. Bush. The Reagans argued that given enough research, embryonic stem cells could treat Alzheimer’s, the disease that led to the death of the former president. Bush defended his 2001 partial ban on stem cell research, maintaining the science is immoral because it means killing embryos that have a potential for life. The only stem cell research he would permit, Bush said, was research using existing embryonic lines as well as so-called adult stem cells, which occur in anyone of any age.
In November California passed a ballot initiative to finance $3 billion in stem cell research, a measure supported by Republican governor Arnold Schwarzenegger. Other states are contemplating similar moves, but the United States is well behind other nations in stem cell research. Bush’s funding restrictions have “had a chilling effect,” says Doug Melton, a stem cell researcher at Harvard University. “It’s discouraged young people from entering the field. They want to base their future on the prospects for doing science, not politics.”
