Chinese scientists said Wednesday that further research is needed in a bid to find a cure for human infertility, despite their claims on Sunday of successfully making infertile female mice pregnant.

"We need to confirm whether the same stem-cell transplant technology can be applied on other mammals, including humans," said Professor Wu Ji with the College of Life Science and Biotechnology of Shanghai Jiao Tong University.

Her article on the discovery of germline stem cells found in mice ovaries was published in the latest issue of "Nature Cell Biology" on Sunday. The article explained her theory of using the cells to make infertile mice produce healthy offspring.

The discovery, however, refuted current scientific theories, saying that there is no germline stem cell in ovaries.

"The research on using the cells to produce eggs to cure mice infertility opened new ground in biotechnology. We need more scientific evidence to support my theory," Professor Wu told Xinhua on Wednesday.

She hoped to introduce foreign cooperation into the next stage of the research, which would focus on establishing the basic theory and exploring the possibility on applying them to humans.

She explained that the research project may give clues to treating human reproductive diseases and preserve endangered species.

Wu said her lab researches led to findings of egg-cell-producing cells in the ovaries of young mice, which are called germline cells.

Her team isolated the cells, examined them grown in the laboratory and then transplanted them into the ovaries of infertile female mice.

Wu's research is currently sponsored by funding from the China National Natural Science Foundation and Shanghai Pujiang Talent Program Foundation.

(Xinhua News Agency April 15, 2009)