As it says at the end:
Dr Collins, who was also a key player in the Human Genome Project, released a statement saying: "The concept of altering the human germline in embryos for clinical purposes has been debated over many years from many different perspectives, and has been viewed almost universally as a line that should not be crossed.
"Advances in technology have given us an elegant new way of carrying out genome editing, but the strong arguments against engaging in this activity remain.
"These include the serious and unquantifiable safety issues, ethical issues presented by altering the germline in a way that affects the next generation without their consent, and a current lack of compelling medical applications."
Dr Marcy Darnovsky, from the Center for Genetics and Society in the US, argued: "There is no persuasive medical reason to manipulate the human germline because inherited genetic diseases can be prevented using embryo screening techniques, among other means.
"Is the only justification for trying to refine germline gene editing the prospect of so-called enhancement?"