New York City is losing some of its top stem cell researchers, and the science community is growing increasingly worried that the industry could suffer severely in coming years if the state does not set aside more funding.

“I know there are concerns at all of the institutions about the potential loss of researchers to California and possibly elsewhere,” the dean of Weill Cornell Medical College, Antonio Gotto Jr., said.

While New York currently boasts some of the most prominent embryonic stem cell researchers in the country, the state has not stepped in to offset the funding restrictions the federal government has placed on the research in the same way California and other states have.

Many in the medical community are banking on the leading candidate for governor, Eliot Spitzer, to take action to ensure New York does not suffer a so-called brain drain.

Mr. Spitzer has already said that if elected he’ll push for a ballot initiative that would allow the state to borrow $1 billion to fund stem cell and other biomedical research over the next decade. While researchers are embracing the idea, opponents say borrowing that much would sink New York into debt. Political and ethical objections could make it difficult to pass the measure.

For now, California, which has already earmarked roughly $3 billion for the research, is edging out New York. Although the $3 billion is currently tied up in court, Governor Schwarzenegger allocated $150 million in July to jumpstart the programs.

In the meantime, New York is losing some of its top talent. Dr. Gotto said one of his stem cell researchers is going to the University of California San Francisco. The dean said the funding was not the deciding factor, but that doesn’t change the loss in a field that is getting harder to recruit into.

Mount Sinai Hospital is about to lose one of the prominent stem cell researchers in the city — Gordon Keller.

Mr. Keller, who last year was named on a New York magazine list of six doctors that New York “can’t lose,” said he was moving because he wanted to relocate to his native Canada and that the decision had nothing to do with the freer stem cell research situation in that country.

His end-of-the-year departure will be a loss for the hospital. Mr. Keller said he was not worried about established New York doctors leaving New York, but said that without government money in the pipeline it would be hard to build the next generation of researchers.

“It’s not going to happen overnight,” Mr. Keller said. “But five years down the road when California has built their centers … New York has, we’ll have trouble.”

He added: “If I were on the other side, recruiting in California, I would certainly use it.”

So far, private foundations and donors have stepped in to rescue the stem cell community. Last year, the Starr Foundation gave a $50 million grant to Weill Cornell Medical College, Memorial Sloan Kettering, and Rockefeller University to conduct stem cell research together. The financier Leon Black donated $10 million to Mount Sinai for a stem cell institute.

The president of Rockefeller University, Sir Paul Nurse, said his institution has been largely protected from the federal funding restrictions imposed in 2001 because it has had private funding, but he said he’s concerned about institutions that don’t have the same access.

Mr. Nurse, who in 2001 won a Nobel Prize for discoveries related to cell cycles, said the most significant threat to New York comes from Europe and the Pacific Rim, which are becoming magnets for the research.

Mr. Nurse and others said they’re counting on a federal policy change in the next few years that would make funding available to study new embryonic stem cell lines. At the moment, federal money is allowed to fund research only on existing lines.

Governor Pataki and the state Legislature failed to reach an agreement on stem cell funding last year.

While the state was considering that legislation, the president of Mount Sinai, Dr. Kenneth Davis, said that while philanthropic support was crucial, it would not be enough for New York to remain a leader in stem cell research.

“If New York is to be counted among the elite group of leaders in biomedical research in the years to come, a large-scale, centralized effort is needed today or we risk losing our intellectual capital, and, thus, our potential,” he said.