After outlandish claims, a few media circuses, and some near misses by legitimate researchers, a team of South Korean researchers reports the production of cloned human embryos. The findings, to be published today (February 12) in
Wook Suk Hwang and Shin Yong Moon of Seoul National University used somatic cell nuclear transfer to produce 30 human blastocysts and a single embryonic stem cell line; SCNT-hES-1. Using 242 oocytes and cumulus cells from 16 unpaid donors, the group achieved a cloning efficiency of 19 to 29%, on par with that seen in cattle (25%) and pigs (26%).
“They have obtained an efficiency that is really amazing,” said Hans Robert Scholer, a professor of reproductive medicine at the University of Pennsylvania. Although several groups have claimed to have grown cloned human embryos...