The controversial Chinese scientist who claimed this week that he helped create the world’s first genetically edited babies now says a second pregnancy from the experiment may be underway. He Jiankui claims to have altered the DNA of twin girls born this month to try to make them resistant to the AIDS virus—his announcement was greeted with skepticism and rebukes from scientists who believe it’s immoral and dangerous to meddle with the genetics of unborn babies. Making his first public comments since the shocking announcement, the researcher claimed a second potential pregnancy is in a very early stage. He also defended his work, saying at a genome summit in Hong Kong that he was “proud” of altering the genes of the twin girls. The scientist also confirmed his school—Southern University of Science and Technology in Shenzhen—was not aware of the experiment, and said that he funded it by himself.