The Japanese are so screwed. But imagine this paradigm in
China, where one-child has grievously imbalanced the male-female ratio, and that first imbalanced generation is coming of age. Some subset of Chinese males are completely s-o-l because of the evil their leaders have propogated in the name of state socialism.
It is interesting you bring up the Chinese. They will have major demographic problems becoming apparent any minute now due to their male-female imbalance. They have a huge, 8 figure cohort of males that will not have an opportunity for marriage. I figure there is a huge burgeoning market for a) prostitutes and b) robotic consorts of some sort.
Over the longer haul, they will have difficulty maintaining population levels as their society grows older.