Debate over ethical questions surrounding the collection of human eggs for stem cell research is intensifying in U.S. academic circles.

The U.S.-based Wall Street Journal made the assertion in reports on the departure of American scientist Gerald Schatten from the research team of South Korean stem cell pioneer Hwang Woo Suk. Schatten abruptly announced earlier this week that he could no longer work with Hwang, claiming that the Korean researcher had unethically obtained human eggs from his female subordinates.

The Journal said if Schatten’s charges are confirmed as true, it would deal a huge blow to U.S. cloning research.

The U.S. daily cited Harvard University professor Kevin Eggan as saying Hwang’s accomplishments carry enormous significance academically and expressing hope that the recently raised suspicions would prove false.

Ann Kiessling, the director of the Bedford Stem Cell Research Foundation in Massachusetts, also reportedly expressed worries that such ethical controversies over egg donation could hold troubling ramifications for cloning research.