Canada last week passed a bill that bans human cloning but permits research using stem cells derived from embryos – research that scientists hope will lead to therapies for many of the worst human diseases.

The bill states that "No person shall knowingly create a human clone by using any technique," which would include therapeutic cloning, a technology researchers believe could lead to revolutionary treatments. The bill still requires "royal assent" from the governor general before it becomes law, but that is considered a formality.

"While it is commendable that Canada will ban reproductive cloning, they are off-base in prohibiting therapeutic cloning," said Bernard Siegel, president of the Genetics Policy Institute. "Some of their brightest scientists will be compelled to find labs elsewhere. Canada loses the opportunity to advance the potentially greatest medical advance of our time, one that promises understanding of mankind's worst afflictions and the regeneration of tissue without rejection."

Therapeutic cloning is based on the concept that the best way to get stem cells that are a perfect match for a patient – thereby preventing immune rejection – will be to create a clone of that patient, develop the embryo to around 100 cells, then remove the stem cells. Researchers consider the technique promising for treating spinal cord injuries and Alzheimer's disease.

Several countries, including China, Japan, the United Kingdom and Singapore, have outlined regulations for embryonic stem-cell research. They allow therapeutic cloning while outlawing reproductive cloning. However, U.S. lawmakers have not been able to agree on any of the handful of cloning bills that have been drafted, leaving the country with a smattering of state laws but no federal mandate. New Jersey and California have passed state legislation to allow therapeutic stem-cell research, and Minnesota and Massachusetts are considering similar laws.

In addition, Canada's bill allows researchers to use embryos leftover from in vitro fertilization treatments to create stem cells, but bans payments to donors of the sperm, egg or whole embryo.

Many researchers have advocated this approach, saying that hundreds of embryos are thrown out or remain frozen indefinitely at IVF clinics.

"They'll stay until there's a power failure or something," said Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania. "Their fate is sealed; they'll never make a baby. And some couples would donate if you asked them."

In the United States, no federal law exists to ban maverick scientists from using cloning technology to create a baby, an endeavor that many legitimate scientists believe would be dangerous. There are also few regulations governing the way scientists can perform stem-cell research.

"Stem-cell research can go on here without regulations," said Caplan. "So you could be paying egg donors or deceiving your egg donors, and it would be hard to know what was going on."

The condition of U.S. stem-cell science is woeful, many researchers say, due in large part to President Bush's restriction on using the cells.

In August 2001, the president declared that no federal funds could be used for work on embryonic stem cells unless the research used the supposed 64 stem-cell lines already derived and registered with the National Institutes of Health as of that date. The NIH later declared that only 15 lines were actually available, and some critics have recently accused Bush of misleading scientists in 2001.

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