Dr He Jiankui yesterday told a packed Hong Kong biomedical conference that he was "proud" to have successfully altered the DNA of twin girls born to an HIV-positive father - an apparent medical breakthrough.
It was first announced earlier this week that Prof He had altered the DNA of embryos - twin girls - to prevent them from contracting HIV.
"The volunteers were informed of the risk posed by the existence of one potential off-target and they chose to implant", He said Wednesday, as he was bombarded with questions about the trial.
Scientists from around the world have condemned the experiment.
He said there had been "another potential pregnancy" involving a second couple, but when questioned further agreed it had been a chemical pregnancy - a term referring to a very early miscarriage. "I don't think it has been a transparent process", Caltech's David Baltimore, who is a leader of the conference, said in a talk following He's, according to Reuters. "And we did not hear answers to those questions".
"In the beginning we did not understand what it was they were really doing". In a country such as the USA, which has up until now been very hands-off when it comes to most uses of assisted-reproduction technologies, there's a very real chance that decisions about whether to use gene-editing in embryos, and in what ways, will eventually be left up to individuals. "It's an appalling example of what not to do about a promising technology that has great potential to benefit society".
"This study has been submitted to a scientific journal for review", he said of his self-funded research, without naming the journal.
In Hong Kong, Organisers of the Second International Summit on Human Genome Editing denounced He's "unexpected and deeply disturbing" claim that human embryos had been edited and implanted, and called for closer supervision of the field at the conclusion of the conference Thursday. "I must apologise, this result was leaked unexpectedly", He Jiankui said, according to AFP. It is still pending scientific peer review and many biologists have criticized the ethics of the experiment.More news: Syria war: Aleppo 'gas attack' sparks Russian Federation strikes
More news: Theresa May's Brexit deal 'meaningful vote' to be held on December 11
More news: Dershowitz says Robert Mueller report won't result in Donald Trump criminal charges
"For this specific case, I feel proud".
He Kaiwen was one of a group of more than 120 scientists who released a statement condemning He's work.
Dr. Kiran Musunuru at the University of Pennsylvania called it "unconscionable.an experiment on human beings that is not morally or ethically defensible".
The Guangdong province Health Commission said on its website on Wednesday it and Shenzhen city had set up a team to investigate the case.
Meanwhile, more American scientists said they had contact with He and were aware of or suspected what he was doing. He said he would monitor the two newborns for the next 18 years and hoped they would support continued monitoring thereafter.
"I couldn't guarantee to you that he did what he claimed", she said.
Feng Zhang, one of the founders of the CRISPR Cas9 technology used in He's experiment and a professor at MIT, told Caixin that DNA editing has a long way to go before being used in embryos.
Others strongly disagree with He's assessment and with his general approach. To act on science before it's considered ready and safe is "going to create misunderstanding, discordance and distrust", he says.