The Seoul National University Hospital has asked cloning pioneer Hwang Woo-suk to reassume his position as head of the World Stem Cell Hub.

Hospital director Seong Sang-cheol on Sunday said no one other than Hwang is qualified to pursue general research and joint projects with overseas institutes.

He said the hub will have an acting chief before Hwang's eventual return to avoid a disruption in the research process.

Hwang on Thursday admitted to ethical lapses in his research and resigned from all of his official posts.

Meanwhile, his assistant Ahn Kyu-ri has received offers for joint research from six to seven institutes abroad during her visit to the United States, and is expected to announce details upon returning home Tuesday.

In addition, the number of women who have offered to donate eggs for stem cell research and infertility has surpassed 700.

A civic group that is leading a donation drive said the number of volunteers has jumped just six days after the group formed, and more so after Hwang's news conference Thursday.