S. Korean Denies He Faked Cloning

South Korean stem cell pioneer Hwang Woo-suk talks to reporters during a press conference at the Seoul National University in Seoul, Friday, Dec. 16, 2005.
South Korean researcher Hwang Woo-suk stood by his reported stem cell breakthroughs Friday despite claims he falsified data — but he said he's asked to withdraw a scientific paper on the research due to errors.

The paper, published in May by the prestigious journal Science, purported to show how Hwang's Seoul-based team used cloning to custom-make embryonic stem cells for 11 patients, raising hopes of a breakthrough treatment for tough ailments like Parkinson's disease and diabetes.

Stem cells are master cells that can grow into all types of bodily tissues and are seen as a potential way to treat numerous ailments by replacing diseased tissue.

Hwang said he asked Science on Friday to withdraw the report due to problems with the accompanying photos, and he apologized for "fatal errors and loopholes in reporting the scientific accomplishment," but didn't give further details.

His team had earlier told Science that some duplicate photos of the same stem cell colonies had accidentally been printed in the journal and presented as separate colonies.

Science's editors have said the mistake didn't affect the findings.

Hwang has also insisted that the basic findings behind the article were sound, and vowed to prove it within days by thawing out five frozen stem cell lines to prove they've been cloned from cells from human donors, reports CBS News' Don Kirk.

"Our research team made patient-specific embryonic stem cells, and we have the source technology to produce them," he said Friday at a Seoul news conference.

But Hwang's former research partner, Roh Sung-il, repeated accusations Friday that Hwang wasn't telling the truth.

Roh — who co-authored the paper with Hwang and is chairman of the board at a leading Seoul hospital — had earlier ignited the firestorm over the research by saying Hwang had pressured a lab worker to falsify research data.

"He's avoiding taking the responsibility that he should take," Roh, who provided Hwang with human egg cells for the research, said Friday at a separate news conference in Seoul.

Roh also questioned Hwang's claims that he created 11 stem cell colonies.

"Nine stem cell colonies appear to be fake and two others are not confirmed yet," Roh later told The Associated Press by phone.

Hwang had earlier insisted that the 11 cell colonies were created "without 1 percent of doubt." At the news conference, he said six of those had been destroyed through negligence.

But Roh said Hwang's attempts would fail to prove the experiments' authenticity.

He said that he'd visited Hwang Thursday, and that Hwang had told him all the cell colonies had died.