They fear the result will be the birth of babies whose every cell has been altered by scientists in a rush to be first. This could happen well before researchers know enough about the consequences of editing genes, before they know how to edit safely and before society can debate if such procedures are even acceptable.

“It is unacceptable to mutate normal embryos,” Dr. Jaenisch said. “For me, that means there is no application.”

“In our view, genome editing in human embryos using current technologies could have unpredictable effects on future generations. This makes it dangerous and ethically unacceptable.”

This is ridiculous. When have scientists ever stopped to think of the long term consequences of their technologies? Why would society object to mutate a normal embryo, when it's already legal to kill normal fetuses and torture animals? China is doing it anyway, and I would bet my right hand that the US government is experimenting with this and other techniques too. What world do these scientists think they live in?