The document discusses issues around population decline in Japan and arguments for and against immigration. It notes Japan's declining birth rate, with mothers' average age for first birth rising to over 30 in 2013. While some argue this is due to "parasite singles" or "herbivore men", the document suggests immigration could help address Japan's population problems. It provides examples of how immigration has benefited other countries economically and through cultural diversity in sports and arts. However, the document also acknowledges some public fear around immigration and how it can be an unpopular policy despite the economic benefits.