A team of U.S. and South Korean researchers reconfirmed Friday that a stem cell line created by discredited cloning scientist Hwang Woo-suk in 2004 was in fact not what he originally claimed it to be.

Hwang, once considered a national hero, was tried on charges of fraud and violating bioethics laws after his team was found in January 2006 to have submitted faked data for embryonic stem cell research to two scientific journals.

The team, led by Kim Ki-tae, a researcher at the Dana-Farber/Harvard Cancer Center in the United States, said they have developed a way to differentiate stem cells created from parthenogenesis and somatic cell cloning.

There has been mounting controversy over the nature of the stem cell line unveiled in 2004, dubbed NT-1 among cloning scientists.

An investigative panel from Seoul National University, where Hwang once worked, said that the cells seem to have been created through parthenogenesis, the development of an ovum without any genetic contribution from a male.

Through analysis of DNA sequences from mouse stem cells created both from parthenogenesis and somatic cell cloning, the team came to the conclusion that the NT-1 was not created by cloning somatic cells as Hwang has insisted, or through what is known as "unisexual reproduction."

George Daley, a professor at the U.S. cancer center who oversaw the study, said that the NT-1 was confirmed to have been created through parthenogenesis.

The team's research was published in the latest edition of the U.S. journal Cell Stem Cell and is the first independently published study concerning the veracity of Hwang's work.