Some scientists in the United States are working to make embryos that are part human, part animal in an attempt to save the lives of people suffering from various diseases. But other scientists warn that such experiments could damage people’s sense of humanity, NPR reports. Such embryos are called “chimeras,” named after creatures from Greek mythology and which are created artificially by combining genetic material from different species into a single embryo.

The adult animals that develop as a result have different populations of cells that reflect different contributions from the species from which they were produced. “We’re not trying to make a chimera just because we want to see some kind of monstrous creature,” NPR quotes Pablo Ross, a reproductive biologist at the University of California, Davis, as saying. “We’re doing this for a biomedical purpose.” READ MORE