Harvard University (search) plans to launch a multimillion-dollar center to grow and study human embryonic stem cells (search), the school announced Sunday.

The center could be the largest privately funded American stem cell research project to date. It must use private funds to create new lines of stem cells because President Bush, citing ethical considerations, has limited federal funding for embryonic stem cell research to existing lines of cells.

Harvard released a statement Sunday confirming its plans, saying the school is "proceeding in the direction of establishing a stem cell institute." The final details were not complete, the statement said.

"This is very important science that has really enormous prospects to benefit humankind," said Provost Steven E. Hyman (search). "Throughout the Harvard system, we have scientists working on different aspects of stem cells. The goal here is to bring them together to create a very strong effort."

Harvard has not decided how much money needs to be raised for the center, Hyman said. Scientists involved told the Boston Sunday Globe that the fund-raising goal is about $100 million.

"Harvard has the resources, Harvard has the breadth and, frankly, Harvard has the responsibility to take up the slack that the government is leaving," said Dr. George Q. Daley, an associate professor at Harvard Medical School and Children's Hospital who is involved in planning the center.

The center, tentatively called the Harvard Stem Cell Institute, would bring together researchers from the university and its affiliated hospitals. About 20 researchers are now working on planning for the center, Hyman said.

Stem cells are found in human embryos, umbilical cords and placentas, and develop into the various types of cells that make up the human body. Scientists hope to someday be able to direct stem cells to grow in laboratories into replacement organs and tissues to treat a wide range of diseases, including Parkinson's and diabetes.

But to harvest embryonic stem cells, researchers must destroy days-old embryos -- a procedure condemned by some religious groups, abortion foes and others.

"Every success will change the argument," said Dr. Leonard Zon, a researcher at Children's Hospital Boston and president of the International Society for Stem Cell Research. "The American people will not stand for scientists not being able to work on their diseases."

Hyman said the Harvard researchers are taking concerns over the use of human stem cells into consideration.

"We've already begun to engage people in the non-science community to help us address ethical and social issues," Hyman said.

Other American research centers also plan privately funded research. Stanford University announced in 2002 a $12 million donation to study cancer by creating human embryonic stem cell lines. The University of Wisconsin, the University of Minnesota and the University of California at San Francisco also have programs.

In California, activists are pushing a $3 billion ballot initiative to finance the work. And the governor of New Jersey said last week that the state would give Rutgers University $6.5 million to create and study new cell lines.