SoftBank Group Corp. said Thursday that it will start medical services in Japan that analyze gene information and other data with artificial intelligence, offering treatment proposals for cancer and other serious diseases. The services, to start later this year, will be provided by establishing a joint venture with Tempus AI Inc., leveraging the U.S. company’s expertise and technology on AI-powered health care and its massive data libraries. “We want to reduce the sorrow of death,” SoftBank Group CEO Masayoshi Son said at a press conference in Tokyo, while revealing that he lost his father to …