He Jiankui recently stated that there is "another potential pregnancy" involving a second couple at a human genome forum in Hong Kong, according to the Xinhua news agency.
The government has reportedly confirmed the existence of the second mother, who is still pregnant and will be put under medical observation, the Xinhua news agency reported, citing sources close to the investigation.
He will be "dealt with seriously according to the law", and his case will be "handed over to public security organs for handling", Xinhua reported.
The announcement of the existence of gene-altered babies has prompted global objections and an investigation by Chinese health authorities with the National Health Commission ordering officials to "seriously investigate and verify" his claims.
The scientific community is worried that genome-editing may cause harm not only to individuals but also to future generations that inherit these same alterations.