Two junior researchers of cloning pioneer Hwang Woo-suk were confirmed to have donated their eggs for stem cell experiments "voluntarily."

The Ministry of Health and Welfare Thursday disclosed the results of an investigation by an ethics panel under the Veterinary Department of Seoul National University on allegations that Professor Hwang had used ova collected from his junior researchers in his stem cell experiments.

The ministry said in a statement that the two researchers had "voluntarily" donated their eggs for the success of Hwang’s stem cell research and that Hwang apparently became aware of their egg donation around May of last year.

The statement said the ethics panel had found no other cases of ova donation by other members in Hwang’s research team.

Meanwhile, an official of the ethics panel told Seoul-based Yonahp News Agency that Hwang is likely to announce his decision to step down as head of the World Stem Cell Hub soon. He is to hold a new conference later in the day to issue an official statement on a series of speculations surrounding his research.