SOUTH KOREA'S pioneering stem cell scientist apologized Thursday for procuring egg cells from two members of his team for research, saying his rush to advance science may have clouded his ethical judgment.

Hwang Woo-suk, who became a hero in South Korea after major developments in cloning research, has been caught in a swirl of allegations over his work after a U.S. collaborator left the group, saying Hwang unethically procured human eggs.

Time magazine called Hwang's team's cloning of a dog the year's most amazing invention. Snuppy was the world's first cloned dog - dogs are considered one of the most difficult animals to clone.

"Being too focused on scientific development, I may not have seen all the ethical issues related to my research," Hwang said.

He told a packed news conference he had become aware earlier this year that the researchers provided egg cells in 2002 and 2003, even though he had turned down their offers to do so.

"At the time technology was not as advanced as today and creating one stem cell line required oocytes (eggs). It was during this time when my researchers suggested making voluntary donations. I clearly turned it down," Hwang said.

Hwang said he could understand their way of thinking and said if he were a woman, he probably would have donated eggs.

Hwang also said he was stepping down as the head of a global stem cell hub, established only last month in South Korea. Hwang will continue his research, but said he was considering leaving once his work was finished.

South Korea's health ministry said prior to the news conference that there was nothing legally or ethically wrong at the time with the egg donations judged by South Korean standards. Several countries consider the type of donation made by Hwang's researchers as a violation of medical ethics that hold a subordinate should not be morally coerced into collaborating.

Editor: Wing