Harvard University on Tuesday announced the launch of a privately funded, multimillion dollar program to create cloned human embryos as sources of medically promising stem cells.

The collaborative effort, involving several Harvard-affiliated medical research centers, the New York Stem Cell Foundation and Columbia University, marks a new phase in the long-simmering U.S. culture war over stem cell research, pitting some of the nation’s most prestigious institutions against a vocal conservative movement that opposes the work.

President Bush banned the use of federal funds for studies of new human embryonic stem cell colonies in August 2001, saying the creation and destruction of human embryos for research ran counter to a “culture of life.” Since then, only the University of California, San Francisco, has acknowledged doing research on cloning human embryos, also using private funding.

The field lost much of its luster earlier this year when Korean claims of having done the first successful derivation of stem cells from cloned human embryos proved fraudulent.

Harvard officials said they had developed their program over a two-year period under an umbrella of new ethics rules and hoped to boost the field without unduly offending opponents.

The work, aspects of which have already begun, involves creating embryos made not by the usual fusing of sperm and egg but by fusing a patient’s body cell – such as a skin cell – with a human egg whose own DNA has been removed. The resulting embryo would be genetically identical to the patient who donated the skin cell, so stem cells derived from it and transplanted into the patient are unlikely to be rejected by the immune system.

In one scenario, stem cells made from a person with sickle cell disease would have the disease-causing genetic defect corrected in the lab, be coaxed to become bone marrow cells and then be reinfused into the patient’s marrow. There they could churn out a lifelong supply of healthy, non-sickling blood cells.

But the more immediate aim is to conduct basic research on the underlying causes of genetically complex diseases, scientists said.

“Clinical applications may be a decade or even more away,” said George Daley of Children’s Hospital Boston, one of the study leaders along with Douglas Melton and Kevin Eggan of the Harvard Stem Cell Institute.

Much of the ethical wrangling leading up to Tuesday’s announcement related to the procurement of human eggs. Under rules ultimately approved by all eight ethics review boards with jurisdiction over the experiments, women will be reimbursed for expenses they directly incur in the process of donating their eggs but will not be eligible for the thousands of dollars they could easily get for donating eggs to a fertility clinic to help other women get pregnant.

Egg donation, which involves a one-month hormone treatment and an outpatient surgical procedure, carries a small risk of serious complications. Harvard researchers said they hoped that women with relatives who suffer from the diseases that will be the initial focus of the work – diabetes and blood disorders and, in years to follow, neurodegenerative diseases such as Lou Gehrig’s disease – might step up to the plate.

Other experiments will use eggs and embryos left over from failed fertility treatments – materials that the researchers said may be easier to obtain but that also may be of lower quality than fresh eggs.