HONG KONG -- The Chinese geneticist who says he has produced the world's first genetically edited children revealed that there was a second potential pregnancy on Wednesday, as he faced an outcry from international scientists over the ethics and safety of his research.
The twin girls, whose basic genetic information was altered to protect them from inheriting HIV from their father, are healthy and will be observed over the next 18 years, He Jiankui told the second Human Genome Editing Summit in Hong Kong.
The twins were born from a fertilized egg provided by one of eight volunteer couples, among whom there may be another pregnancy in progress, said He, an associate professor at Shenzhen's Southern University of Science and Technology. Further genome experiments will be put off, he said.
He did not elaborate on the second pregnancy, except that it is in an early stage.
Researchers at the summit immediately denounced He for not disclosing the research until news of his results suddenly broke this week.
"I don't think it has been a transparent process," said David Baltimore, a Nobel Prize-winning biologist at the California Institute of Technology who chaired the conference's organizing committee. "We've only found out about it after it's happened and after the children are born."
Fellow scientists also took issue with the lack of peer review on He's work. He presented data intended to show that the project was safe and the children were immune to HIV, the virus that causes AIDS, at the cellular level. But the presentation was unconvincing, said Feng Zhang, a core member of the U.S. Broad Institute research center.
As to the facts of the children's birth and whether any unforeseen abnormalities arose, the truth remains unclear, said Hidenori Akutsu, a biologist at Japan's National Research Institute for Child Health and Development.
An official at China's Ministry of Science and Technology said such a process would represent illegal activity and, if confirmed, would be dealt with under applicable laws. The Chinese government has ordered local authorities to investigate the matter.
He's very goal of preventing HIV through genetic editing was portrayed as excessive. Unlike some other incurable and hereditary diseases, HIV can be kept from passing on to children by simpler means, such as treating an infected man's sperm to remove the virus before in vitro fertilization.
The geneticist's research cannot be called treatment, said Qiu Renzong, a bioethics expert at the Chinese Academy of Social Sciences. Qiu said his experiment is in fact closer to creating so-called "designer babies" modified to select traits at the genetic level -- a process some warn could lead to ideas of eugenics.
Objections arose on the ethical front as well. Most researchers do not deny that genetically editing fertilized eggs may help treat disease in the future. But genome modifications would also be passed down to a person's descendants, and any resulting abnormalities may not become known until it is too late to address them.
For that reason, researchers from around the globe -- including China -- are carefully and thoroughly discussing the matter. Attendees at the first genome editing summit in 2015 concluded that it was too early to set conditions under which to allow the editing of genomes to treat disease.
Many countries are working to set up legal frameworks on the matter based on international discussions. The process is being advanced carefully, with a leading school of thought suggesting that editing fertilized eggs only be allowed for fundamental research, such as studying how diseases work.
He's research appears to ignore the international consensus and show the limits of independent research. Such haphazard experimentation may lead to heightened criticism and mistrust of new technologies, impeding research and the quest to help disease sufferers.