In his zeal to be associated with a cloning breakthrough, a U.S. stem-cell scientist engaged in "research misbehavior" by signing his name to a now-discredited study by a South Korean expert without properly verifying the work, a university panel said Friday.

Dr. Gerald Schatten did not deliberately fabricate data himself, but committed "a serious failure that facilitated the publication" of the paper by Dr. Hwang Woo-suk, the University of Pittsburgh Research Integrity Panel concluded.

In what has turned out to be one of the biggest scientific hoaxes in years, the paper falsely purported to show the creation of stem cells from the world's first cloned human embryos.

The panel was also critical of Schatten's acceptance of $40,000 from Hwang over 15 months.

It said the amount seemed "far above normal honoraria for consultation."

The panel did not recommend any disciplinary action against Schatten, saying it would leave that to officials at the medical school.

Schatten remains a tenured professor and active researcher at the university, officials said. He has not spoken publicly on the scandal since it broke last year. He has an unlisted number, and the university said he is not speaking to the media.

A South Korean academic panel recently determined that Hwang fabricated data to support his claim, published last year in the journal Science, that he cloned human embryos and extracted stem cells from them.

It also concluded Hwang falsely claimed to have developed 11 stem cell lines tailored to specific patients.

The reported cloning breakthrough had offered false hope to millions of people suffering from paralysis and diseases such as Alzheimer's and Parkinson's.

The U.S. panel's investigative report painted Schatten as a researcher eager to enhance his reputation by closely linking himself to Hwang's work.

It found that Schatten, as co-author of the Science article, "did not exercise a sufficiently critical perspective as a scientist."

In its strongly worded report, the panel said Schatten joined forces with Hwang to help a colleague he admired and to help himself through "enhancement of his scientific reputation, improved opportunities for additional research funding, enhanced positioning for pending patent applications, and considerable personal financial benefit."

In another one of Hwang's papers, on the cloning of a dog, Schatten's only contribution as co-author was to suggest that a professional photographer take the dog's picture, the panel said. Independent tests indicate Hwang's claims to have cloned a dog are true.

Schatten, Hwang's sole American collaborator, ended their 20-month partnership in November, before the hoax was revealed but after Hwang had come under fire for using eggs in his studies donated by junior researchers on his team.

Schatten also asked Science to remove his name as senior author of the paper.

Schatten made a "concerted and deliberate effort" to distance himself from Hwang despite having invested "a tremendous amount of time and energy" on drafts of the Science paper, the panel said in its report.

"This is in sharp contrast to the full participation of Dr. Schatten in the media spotlight following publication of the paper," the panel said.