HONG KONG: A Chinese scientist at the centre of an ethical storm over what he claims are the world’s first genetically edited babies said on Wednesday he is proud of his work and revealed there was a second “potential” pregnancy as part of the research.

He Jiankui, an associate professor at Southern University of Science and Technology in Shenzhen, China, addressed a packed hall of around 700 people attending the Human Genome Editing Summit at the University of Hong Kong.

“For this case, I feel proud. I feel proudest,” He said, when challenged by several peers at the conference.

Asked whether there were any other edited gene pregnancies as part of his trials, He said there was another “potential” pregnancy and replied “yes” to a follow-up question as to whether it was a “chemical pregnancy”, which refers to an early-stage miscarriage.

It was unclear whether the pregnancy had ended or not.

He, who said his work was self-funded, shrugged off concerns that the research was conducted in secrecy, explaining that he had engaged the scientific community over the past three years.

“This study has been submitted to a scientific journal for review,” He said. He did not name the journal and said his university was unaware of his study.

In videos posted online this week, He said he used a gene-editing technology known as CRISPR-Cas9 to alter the embryonic genes of twin girls born this month.

He said gene editing would help protect the girls from infection with HIV, the virus that causes AIDS.

But scientists and the Chinese government have denounced the work that He said he carried out, and a hospital linked to his research suggested its ethical approval had been forged.

The conference moderator, Robin Lovell-Badge, said the summit organisers were unaware of the story until it broke this week.

CRISPR-Cas9 is a technology that allows scientists to essentially cut and paste DNA, raising hope of genetic fixes for disease. However, there are concerns about safety and ethics.

The Chinese Society for Cell Biology in a statement on Tuesday strongly condemned any application of gene editing on human embryos for reproductive purposes and said that it was against the law and medical ethics of China.

He, who said he was against gene enhancement, said eight couples were initially enrolled for his study while one dropped out. The criteria required the father to be HIV positive and the mother to be HIV negative.

Scientists at the conference pressed He to prove that those taking part in the trial were aware of all the risks involved in the process.

He said that all the participants had a “good education background” and went through two rounds of discussions with him and his team.

The Guangdong province Health Commission announced on its website on Wednesday that it and Shenzhen city had set up a joint team to investigate the case.—Reuters

Published in Dawn, November 29th, 2018