We may be one step closer to making the film Junior a reality after scientists in Japan successfully created mice with two biological fathers by generating eggs from male cells. Previously, scientists had created mice with two fathers but it required several elaborate steps and included genetic engineering. The latest breakthrough is the first time viable eggs have been generated from male cells in what The Guardian described as a “significant advance” that “opens up radical new possibilities for reproduction.” Lead researcher Katsuhiko Hayashi, from Kyushu University in Japan, presented the findings at the Third International Summit on Human Genome Editing in London on Wednesday. Hayashi predicted the practice could be replicated in humans within a decade but others have suggested that timeline is unrealistic given that viable, lab-grown human eggs haven’t yet been created from female cells, let alone male cells.