Pacific Fertility Center, an in-vitro fertilization clinic in San Francisco that was planning to be part of the consortium, said Monday it was pulling out after the withdrawal Friday of the South Korea-based cloning network's primary U.S. organizer, Gerald Schatten of the University of Pittsburgh School of Medicine.

The collapse is a setback for advocates of creating "disease-specific" lines of stem cells, which involves insertion of DNA from patients into human eggs whose own DNA is first removed, a cloning technique known as "somatic cell nuclear transfer." Researchers say disease-specific cell lines can be powerful tools for studying the origins of genetic disease and finding new drugs to cure them.

Laboratories at South Korea's Seoul National University are at the forefront of the nuclear transfer field under the leadership of cloning specialist Woo Suk Hwang. He and colleagues announced the creation of a "world stem cell hub" on Oct. 19 that was to have included new labs in San Francisco.

The idea, which was still sketchy, was to create stem cell lines in San Francisco and ship them to South Korea for detailed study.

Now, those plans are in tatters.

Schatten was the first to announce he was no longer willing to take part in the venture, citing "misrepresentations" by his South Korean collaborators.

His biggest concerns had to do with the apparent participation as egg donors of female researchers within Hwang's laboratory group. That is not allowed in mainstream laboratories in the United States and elsewhere in the world because of the potential for coercion. Bioethics experts also questioned the lab's apparent failure to disclose some long-term health risks of egg extraction. Harvesting eggs, also known as oocytes, from humans requires an invasive procedure and the use of potent hormones to stimulate the ovaries.

Concerns about the health risks to egg donors has been an issue for California's Proposition 71 program, overseen by the California Institute for Regenerative Medicine in San Francisco, created by the voters with a $3 billion public bond authorization to pursue human embryonic stem cell research. Women rarely suffer severe complications from the procedure, but some donors have died from egg extraction as part of in-vitro fertilization procedures.

Jesse Reynolds, director of a project on biotechnology accountability at the Center for Genetics and Society, a nonprofit group in Oakland, said several red flags were raised by the South Korea project from the beginning.

"It seemed to set up an international system of trafficking in human oocytes, and we couldn't see where the oversight was going to come from," Reynolds said. "Eggs are one of the most critical issues. That's a bottleneck in this vision of the research."

Some West Coast biomedical organizations, including Stanford University, UCSF and the California Institute for Regenerative Medicine, also had expressed reservations about the venture and were declining to participate. Schatten declined Monday through a university spokeswoman to answer questions. Hwang did not return an e-mail request for an interview.

In a written statement Friday, Schatten said he was quitting his 20-month relationship with the South Korea group after "a breach of trust about possible egg-donor recruitment irregularities." Recent news accounts in South Korea have disclosed arrests of some in-vitro fertilization practitioners under a new law banning commercial trafficking in human eggs. One of Hwang's collaborators was identified among those singled out by the authorities.

Schatten didn't offer details about what happened in South Korea, but he left no doubt that he had lost faith. He said he had heard information on Thursday suggesting that "misrepresentations might have occurred" regarding the egg donors.

"The nature of this information mandates confidentiality. I have contacted appropriate academic and regulatory agencies regarding this new information and accordingly, have suspended my collaborations with Professor Hwang," Schatten said in the release.

Dr. Philip Chenette of the Pacific Fertility Center in San Francisco said his clinic also was canceling.

"With Dr. Schatten's withdrawal, it is impossible for us to establish the ethics of the whole thing," Chenette said during an interview.

Dr. Arnold Kriegstein, head of UCSF's stem cell program, said he was never convinced that the South Korea hub was the best way to advance the science of nuclear transfer in human cells. He said the latest developments underscored the need to move carefully.

"The science will go forward despite this problem," Kriegstein said.

A committee of bioethics advisers is drafting standards to guide research financed by the Prop. 71 program in California. A recommendation is expected to reach top policymakers in February.

Geoffrey Lomax, an institute staff member working with the advisory group, said a separate effort may be needed to establish clear international rules.

"It would not surprise me if there were more of a movement in this direction," he said Monday, noting that without a uniform set of rules it might be difficult for scientists in different locations to share materials or join in collaborations.

E-mail Carl Hall at chall@sfchronicle.com.

This article appeared on page A - 11 of the San Francisco Chronicle