The revelation raised more ethical concerns over the project by Dr He Jiankui, an associate professor at the Southern University of Science and Technology in Shenzhen, with an expert questioning why the two experiments, which represented the basic and advanced stages of gene-editing research, had been conducted at the same time.
"First, I must apologize that this result was leaked unexpectedly", He told some 700 attendees. He revealed it Monday in Hong Kong where a gene editing conference is getting underway, and previously in exclusive interviews with The Associated Press.
The Chair of the Summit, Nobel Laureate David Baltimore, spoke from the floor after the panel session.
"So I think the biggest question mark is there", he said. "Only found out about it after it happened and the children were born", he said.
He said: "I feel a strong responsibility that it's not just to make a first, but also make it an example". Mainstream scientists have condemned the experiment, and universities and government groups are investigating.
Alta Charo, a highly respected University of Wisconsin bioethicist who helped organize the summit, issued an even harsher critique of He's work, calling it "misguided, premature, unnecessary and largely useless". The genetic father is said to be HIV-positive.
"There's any number of things that we could do to change the qualities of human beings themselves and make them, in a sense, super-humans". In fact, this was essentially an unnecessary enhancement procedure that would be associated with risks that do not have offsetting benefits.
"Scientists who go rogue ... it carries a deep, deep cost to the scientific community", Daley said.
Antonio Regalado, senior editor for biomedicine for MIT Technology Review - the publication which first highlighted the trial on Sunday - said He's talk was "ethically a half-baked mess". Meanwhile, those who supposedly were involved in approving an ethical review of the experiment that He Jiankui said he conducted are distancing themselves.
"We just saw it on the internet".
Last September, scientists at Sun Yat-sen University used an adapted version of gene-editing to correct a disease-causing mutation in human embryos.
But Daley argued that a consensus was a emerging that "if we can solve the scientific challenges, it may be a moral imperative that it should be permitted".
The scientist said, however, he wanted to prevent HIV being inherited from a parent because so many children were affected by the virus in China.
"The lack of transparency and disregard for risk are deeply concerning", Doudna said.
"I do think the principle of self-regulation is defensible", he says.
They planned to delete the genes linked to CCR5, a cell surface receptor used by HIV to enter and infect cells. Scientists have long searched for ways to block this pathway to protect people from HIV.
The National Health Commission on Monday ordered local officials in Guangdong province -where Shenzhen is located - to investigate He's actions.
"So, when we make changes in the genes, we don't know what else downstream is being changed".
CRISPR-Cas9 is a technology that allows scientists to essentially cut-and-paste DNA, raising hope of genetic fixes for disease.
Editing the genes of embryos is banned in many countries because DNA changes passed to future generations could have unanticipated effects on the entire gene pool. Designer babies are desirable by definition and if there's enough demand, the scientific marketplace will find a way to meet it.
"All of us here at this conference are struggling to figure out what was done and also whether the process was done properly", she said. It also emerged that none of He's presentation slides had contained information about the implanted embryos-or the babies-when they were submitted to the conference organizers.