MOUNTAIN VIEW, Calif. -- Two years ago I pledged to donate $150 million to create a center for biomedical engineering and science at Stanford. Now Congress and the president are thwarting part of the intended purpose of this center by supporting restrictions on stem cell research and cloning. While only a portion of Stanford's plans involve stem cells, I believe research that uses them is vital to the future of medicine. I am therefore suspending $60 million of my remaining pledge pending the outcome of ongoing political deliberations.

After forming Silicon Graphics , Netscape and Healtheon, I felt that the next wave of exciting scientific discoveries and entrepreneurism would come from the combination of molecular biology and technology. John Hennessy, president of Stanford, who shares this conviction, introduced me to Greg Kovacs, a Stanford electrical engineering professor already working in this field. Mr. Kovacs's most fascinating project involved cultivating embryonic chicken cells. His team had coaxed them to evolve into heart cells, which were grown into a thin, beating layer over an integrated circuit. This little biocomputer was like a canary in the coal mine, detecting minute traces of chemicals that would alter the beat of the heart cells.

What intrigued me most about Mr. Kovacs's work was the implication that it might be possible to create human heart cells from human embryonic stem cells. I saw a new future for medicine and biology and for resulting entrepreneurship, and I was inspired to make a grant to help create an environment where this type of research could be done.

Lately, stem cell research and cloning have caught the attention of Washington. Driven by ignorance, conservative thinking and fear of the unknown, our political leaders have undertaken to make laws that suppress this type of research.

Cloning a complete human being violates something intrinsic to our moral sense, and to my knowledge, no one at Stanford is interested in this. Nonreproductive cloning, or therapeutic cloning, however, is simply a process to create genetically compatible cells. Perhaps it should not be called cloning at all. Its purpose is simply to create cells that will not suffer rejection when combined with normal bodily tissue. To that end, it is less objectionable than destroying an embryo created by normal fertilization.

A law prohibiting nonreproductive cloning is inappropriate. A more rational approach is to regulate it, as the United Kingdom has done. It now seems that creating genetically compatible new skin cells for burn victims, pancreas cells for diabetics, nerve cells for those with spinal cord injuries and many, many other potential advances will soon be illegal in the United States.

Compounding our problem, President Bush has unequivocally stated that no federal funding will be available for human stem cell research on future embryos. Astonishingly, he insists that he will not change his mind.

Restricting our researchers to 60 or any other number of existing stem cell lines is beyond comprehension. Who can say, in such a nascent field, that existing lines will not die, that they will not become contaminated, or that they have not already specialized in unknown ways? Moreover, the problem of gaining access to existing lines wastes valuable time by directing researchers' energies in unproductive ways.

  Having taught electrical engineering at Stanford and benefited there from federal research funds, I can say that with no prospect of federal support, significant scientific inquiry in a field like stem cell research will stop. No research leader can forgo federal money.

Denying financing for this biomedical research will drive the formation of a new pharmaceutical industry outside the United States. Federally funded research helped create America's economic leadership in the Internet and computer technology. It led to the formation of companies like Silicon Graphics, Sun Microsystems , Cisco and Netscape. Restricting stem cell research for even a few years simply means that scientists in the United States will not be pioneers. Others will own the patents and claims, and a new pharmaceutical industry will thrive elsewhere.

I believe our country risks being thrown into a dark age of medical research. Biologists are at the threshold of the most important set of discoveries in history, and rather than teach and lead, our politicians react and follow a conservative few. This legislative action will cause the United States to miss a revolution in biology. Meanwhile, in the United Kingdom a new industry will be born.

It is futile to think that private funding can make up what is being lost to laws driven by conservative politics. I therefore have reluctantly decided to suspend further contributions until our lawmakers decide to pursue what I believe to be a rational course in this vital part of our national future.

Jim Clark is the founder of Silicon Graphics, Netscape, Healtheon (now WebMD) and myCFO. He is on the board of Shutterfly, myCFO and DNA Sciences.