Kathy Niakan, an expert at the Francis Crick Institute in London, said: "If true.this would be a highly irresponsible, unethical and risky use of genome editing technology".
Others called for extensive scrutiny regarding Jiankui's claims, including one of CRISPR's co-inventors, Dr. Jennifer Doudna of UC Berkeley, who said that the work needs to be verified before it can be substantiated.
Most mainstream scientists think it's too unsafe to try, and some denounced the Chinesereport as human experimentation. The goal, he said in the interview, was to produce babies with the ability to resist HIV infection in the future by disabling CCR5, a gene that enables the virus to take hold.
Qiu said a lack of regulation mean that scientists often face no punishments as they are only required to abide by the rules of their institutions, which may not stipulate punishments for misconduct.
While He has not yet released a scientific paper, his lab published five YouTube videos about its work Sunday night. "No known diseases. Gene editing itself is experimental and is still associated with off-target mutations, capable of causing genetic problems early and later in life, including the development of cancer".
I feel a strong responsibility that it's not just to make a first, but also make it an example.
"If this is a false report, it is scientific misconduct and deeply irresponsible", Robert Winston, emeritus professor of fertility studies and professor of science and society at Imperial College London, tells BBC News.
Some scientists were astounded to hear of the claim and strongly condemned it.
The professor, who was educated at Stanford University in the United States and works from a lab in the southern Chinese city of Shenzhen, said the twins' DNA was modified using CRISPR, a technique which allows scientists to remove and replace a strand with pinpoint precision. "It's a big deal".
Church told the AP that, when weighing the risks of using CRISPR against the public health threat of HIV, "I think this is justifiable".
"The gene that was edited was not associated with a serious condition".
So far the tool has only been used on adults to treat deadly diseases, and the changes only affected that person. Editing sperm, eggs or embryos is different - the changes can be inherited. In the US, the process is only permitted for lab research. "This suggests that the research of gene editing in China not only has a promising potential, but also is responding to the public's needs".
The scientist, He Jiankui of Southern University of Science and Technology in Shenzhen, China, says he used a technique called CRISPR/Cas9.
But He's claims have not been verified by outside scientists, and there are questions about how the work was conducted. Because there's (supposedly) been an worldwide agreement not to do such experiments on human embryos. "There are safe and effective ways to protect children from HIV transmission, so the study as reported does not appear to address an unmet medical need".
He recruited couples through a Beijing-based AIDS advocacy group called Baihualin.
Gene editing is far too important to surrender to alarmism. First, sperm was "washed" to separate it from semen, the fluid where HIV can lurk. "Many of them thought the research gave them a chance to have babies who do not have the risk of getting HIV". Currently, scientists were supposed to be restricted to editing somatic cells (the ones not involved in reproduction).
"It's nearly like not editing at all" if only some of certain cells were altered, because HIV infection can still occur, Church said. In the US, a gene-editing expert at the University of Pennsylvania told The Associated Press that it was "an experiment on human beings that is not morally or ethically defensible", while a Harvard University geneticist said the research is "justifiable".
He lays out his ethical principles in one of the YouTube videos, including this statement: "No one has a right to determine a child's genetics except to prevent disease".
In an e-mail, Annas voiced skepticism of He's claim but said there are a number of ethical concerns if the researcher is, in fact, telling the truth.
"That might be a layman's way of describing it", he said.
Both men are physics experts with no experience running human clinical trials. "Clearly it is a fraud", said Qiu.
The work, which also involved USA bioengineer Michael Deem, was not peer-reviewed. Making one change for the desired effect can apparently result in other, unanticipated changes down the line.
He sought and received approval for his project from Shenzhen Harmonicare Women's and Children's Hospital, which is not one of the four hospitals that He said provided embryos for his research or the pregnancy attempts.
Some staff at some of the other hospitals were kept in the dark about the nature of the research, which He and Deem said was done to keep some participants' HIV infection from being disclosed.
"Why not view God working through CRISPR if we view God working through chemotherapy?" he said. "I understand my work will be controversial, but I believe families need this technology", he says in one of the videos.