What do the tie-dyed environmentalists at Greenpeace and the Council of Canadians have in common with the Republican party's socially conservative hard core? Both groups are fighting hard to protect the sanctity of life from the march of science.

On Tuesday, U.S. House of Representatives Majority Whip Tom DeLay declared that therapeutic cloning, a procedure many scientists believe will be necessary to develop a wide array of new medical technologies, "would reduce some human beings to the level of an industrial commodity." The procedure, he said, is "unholy" and "is no better than medical strip mining." Mr. DeLay also does not care for research on embryonic stem cells. In a recent statement, he joined two fellow Republicans in calling it "an industry of death."

Fiery stuff. But change a few key words, replace Mr. DeLay's suit with an Earth Day T-shirt, and suddenly you've got yourself a tree hugger. The same day Mr. DeLay was delivering his oration in Washington, activists at a press conference in Winnipeg were denouncing the Canadian government's plans to test genetically modified wheat. Greenpeace, naturally, was leading the charge. The group declares on its U.S. Web site that the genetic engineering industry threatens farmers and the environment alike through "the patenting of life." Maude Barlow, head of The Council of Canadians, feels the same way. She has declared that genes "belong to the Earth and all species; no one has a right to appropriate them or profit from them. All must be declared a public trust to be protected by all levels of government and communities everywhere for all time."

What we are witnessing is the golden age of "life" as a policy position. Depending on their place on the political spectrum, pundits and politicians argue that life should not be pre-empted (embryonic stem cells), copied (therapeutic cloning) or changed (genetically modified foods). Appeals to life's sanctity are even spilling over to inorganic matter. Ms. Barlow believes that, though Canada accounts for 20% of the world's fresh water but just 0.5% of the global population, thirsty nations should not be permitted to drink from our rivers. Why? Because, according to Ms. Barlow, water is "the very source of life."

In all cases, principle is running up against science. Tom DeLay and Ms. Barlow, polar opposites politically, are united in the view that "life" is more important than lives. Many of the diseases that are likely to rip you and me apart over the coming decades -- Parkinson's, heart disease, Alzheimer's, diabetes and arthritis to name just a few -- result from the disruption of cellular function or the destruction of tissue within our bodies. Embryonic stem cells offer hope because they can develop into virtually any human cell type. It is likely that only a few thousand embryos -- each being of the days-old type women occasionally miscarry days into a pregnancy without being aware that they miscarried or even that they were pregnant to begin with -- would be required to generate the stem cell lines required for research. Given the billions of lives that may be saved in the long run, few scientists in the field would agree that they are engaged in an "industry of death."

The argument over genetically modified foods is similar. Even as alarmist fears of dead butterflies and uncontrollable allergens have been debunked, the ardour of environmentalists has remained undimmed. Most refuse to recognize the fact that genetically modified foods are set to revolutionize Third World agriculture. When scientists develop life-saving crops that flourish in harsh climates and soils, they dismiss it as a propaganda trick. It is obvious environmentalists are not concerned about the practical consequences of GM plantings so much as their Gaian sensibilities are appalled by the very concept of harnessing life for profit. It is a matter of principle: Mr. DeLay would place restrictions on research so that insentient human embryos would not be destroyed; Ms. Barlow would make the same sacrifice on behalf of organic potatoes.

On Tuesday, a majority in the U.S. House of Representatives voted with Mr. DeLay in favour of a bill that would outlaw the therapeutic cloning techniques that are expected to be an important component of stem cell research. Speaking against the bill, James Greenwood, a Republican, declared his opponents were "violat[ing] the constitution" by seeking to trump science with religion. Unfortunately for those of us destined to die from Parkinson's and heart disease, he's got it wrong. Under U.S. law, legislators can approve or reject legislation for any reason they wish -- even one that would allow human suffering as the price of abstract principle.