New allegations of fraud in stem cell research by a prominent South Korean researcher emerged Thursday, and scientists said his other high-profile claims could face investigation as well. Among them: the first cloned human embryos and the first cloned dog.

The reputation of Hwang Woo-suk of Seoul National University has been battered by allegations of fabrication in a blockbuster paper published in May. He and co-authors claimed that by cloning human embryos, they’d created 11 stem cell lines that genetically matched certain patients.