A U.S. scientist says he is withdrawing from a stem cell research project led by a team of South Korean scientists because of concerns over a possible breach of ethics.
Gerald Schatten of the University of Pittsburgh, in the northern U.S. state of Pennsylvania, has been working for more than a year with the team, which is led by Hwang Woo-Suk. Mr. Hwang announced last year that his team was the first to clone human embryos and extract embryonic stem cells from them.
Mr. Schatten says he is withdrawing over allegations the South Korean scientists used eggs donated by a female member of the team. Widely held ethics principles preclude scientists from accepting donations from underlings in order to avoid any suggestions of coercion.
Questions have also been raised as to whether the woman was paid for the eggs.
Mr. Hwang has denied allegations of ethical impropriety.
Some information for this report provided by AP.