He Jiankui says it is now possible to rewrite the very blueprint of life. "Science operates under a social licence - scientists work within limits defined by broader community concerns", said Darren Saunders, associate professor in the school of medical sciences at the University of New South Wales, in an emailed statement.
"Grossly premature and deeply unethical", is how noted US bioethicist Henry Greely of Stanford University characterized the claim.
A Chinese researcher says he's the first person to successfully "edit" the genes of babies before birth in a practice the United States bans as unsafe and unethical. Mitalipov was the first scientist to report using CRISPR to successfully edit human embryos, but stopped far short of trying to use them to make babies.
He says he used gene editing to make babies resistant to infection with HIV, the virus that causes AIDS.
The reports fall in the grey area between attempts to cure diseases, and the dreaded "designer baby" scenario, where humans could be modified for benefits unrelated to health (potentially expanding to include intelligence, aesthetics and more).
He claims that the parents involved in the study have declined to be interviewed, and also refused to disclose the location of where the research was carried out.
He's claim has not been independently confirmed or published in a journal where other experts could review his work.
Church and He are among hundreds of scientists gathering at the Second International Summit on Human Gene Editing in Hong Kong.
I feel a strong responsibility that it's not just to make a first, but also make it an example.
"Society will decide what to do next" in terms of allowing or forbidding such science, he added.
There is no independent confirmation of Mr He's claim, and it has not been published in a journal, where it would be vetted by other experts.
"In that child, there really was nearly nothing to be gained in terms of protection against HIV and yet you're exposing that child to all the unknown safety risks", Dr. Kiran Musunuru, a University of Pennsylvania gene editing expert and editor of a genetics journal, said.
George Church, from Harvard, however, defended this research.
"We have to be responsible for the people's health and will act on this according to the law", it said in a statement. Then He performed what he called "gene surgery" and added the gene editing tools to the fertilized egg.
They include Feng Zhang and Jennifer Doudna, inventors of a powerful but simple new tool called CRISPR-cas9 that reportedly was used on the Chinese babies during fertility treatments when they were conceived. In the United Kingdom, editing of embryos may be permitted for research purposes with strict regulatory approval. He has even applied for patents for some of his methods as a result of his study. "There are so many ways to adequately, efficiently, and definitively protect yourself against HIV that the thought of editing the genes of an embryo to get to an effect that you could easily do in so many other ways in my mind is unethical".
He's goal was to disable a gene called CCR5, a protein co-receptor that creates a doorway for HIV to enter the host cell. He told the AP that since HIV is "a major and growing public health threat" he finds such experiments "justifiable". Alta Charo, a bioethicist at the University of Wisconsin at Madison, notes that the National Academies report does mention CCR5 as a potential target of gene editing.
Instead, the appeal was to offer couples affected by HIV a chance to have a child that might be protected from a similar fate.
First, He washed the sperm which separated it from the semen, where the HIV virus can be found. Also, some so-called mitochondrial disorders can be addressed by using some genetic material from mom and some from a donor egg, along with dad's sperm. At this point, couples were told that they could choose whether to use edited or unedited embryos for their pregnancy attempts.
So far, one of the twins had both copies of the edited gene-altered while the other twin had just one altered. The technology also carries the risk of affecting other genes unintentionally. People who inherit this trait naturally resist HIV infection.
"Of course the work occurred", Deem said.