A Chinese researcher who claims to have helped make the world’s first genetically-edited babies has said a second pregnancy may be under way.
The researcher, He Jiankui of Shenzhen, revealed the possible pregnancy as he made his first public comments about his controversial work at an international conference in Hong Kong.
He claims to have altered the DNA of twin girls born earlier this month to try to make them resistant to infection with HIV.
Mr He said: “They need this protection since a vaccine is not available.”
Mainstream scientists have condemned the experiment, and universities and government groups are investigating.
The second potential pregnancy is in a very early stage and needs more time to be monitored to see if it will last, Mr He said.
The conference leader called Mr He’s experiments “irresponsible”, and said it provided evidence that the scientific community had failed to regulate itself to prevent premature efforts to alter human DNA.
The work is highly controversial because the changes can be inherited and could go on to harm other genes, and is banned in many countries.
Jennifer Doudna, a University of California-Berkeley scientist and one of the inventors of the CRISPR gene editing tool which Mr He claimed to have used, said: “This is a truly unacceptable development.
“I’m grateful that he appeared today, but I don’t think that we heard answers. We still need to understand the motivation for this.”
David Liu of Harvard and MIT’s Broad Institute, the inventor of a variation of the gene editing tool, said: “I feel more disturbed now.
“It’s an appalling example of what not to do about a promising technology that has great potential to benefit society. I hope it never happens again.”
There is no independent confirmation of Mr He’s claim and he has not yet published in any scientific journal where his work would be vetted by experts.
At the conference, Mr He failed or refused to answer many questions, including: who funded him, how did he ensure that participants understood the potential risks and benefits, and why did he keep his work secret until after it was done?
After Mr He spoke, David Baltimore, a Nobel laureate from the California Institute of Technology and a leader of the conference, said the scientist’s work “would still be considered irresponsible” because it did not meet criteria many scientists agreed on several years ago before gene editing could be considered.
Mr Baltimore said: “I personally don’t think that it was medically necessary.”
The case shows “there has been a failure of self-regulation by the scientific community” and said the conference committee would meet and issue a statement on Thursday about the future of the field, Mr Baltimore added.
Before Mr He’s talk, Dr George Daley, Harvard Medical School’s dean and one of the conference organisers, warned against a backlash to gene editing because of Mr He’s experiment.
Dr Daley said that just because the first case may have been a mis-step, this “should in no way, I think, lead us to stick our heads in the sand and not consider the very, very positive aspects that could come forth by a more responsible pathway”.
“Scientists who go rogue … it carries a deep, deep cost to the scientific community,” Dr Daley added.
Regulators have been swift to condemn the experiment as unethical and unscientific.
China’s National Health Commission has ordered local officials in Guangdong province to investigate Mr He’s actions, and his employer, Southern University of Science and Technology of China, is also investigating.