A Chinese scientist who claims to have created the first genetically modified babies in the world defended his work.
Speaking at a genomics summit in Hong Kong, He Jiankui, an associate professor at a Shenzhen university, said he was "proud" of his work.
He added that "another potential pregnancy" of a gene-modified embryo was in its infancy.
His claims, which provoked widespread outrage, have not yet been independently verified.
University Prof He, South Shenzhen University of Science and Technology, said that she was not aware of the research project and that she would be launching investigation.
It was announced earlier this week that Professor He had modified the DNA of embryos – binoculars – to prevent them from contracting HIV.
His claims have been widely criticized by other scientists, who have described the idea as monstrous. This work is prohibited in most countries.
"Normal and healthy"
On Wednesday, Professor He spoke for the first time to an audience of his work since the tumult.
He revealed that the twin girls – called "Lulu" and "Nana" – were "born normally and in good health," adding that he was expected to monitor the twins over the next 18 years.
He explained that eight couples – composed of HIV-positive fathers and HIV-negative mothers – had voluntarily enrolled for the experiment; a couple later gave up.
He added that he had initially funded the experiment by himself.
Professor He also stated that the study had been submitted to a scientific journal for review, although he did not name the newspaper.