In china no marriage is allowed before the age of 24. In addition no couple is allowed to have more than one child. The second child is illegal and often during the time of pregnancy ends in an abortion. Also all the government grants for the family is withdrawn. (if there is an attempt to have a second child or second child is delivered)
Although in most rural areas second child is permitted if the first one is a girl child. 3 childs are allowed for larger minorities like Tibetian, Uighur and Mongolians.
Due to all these there is a great imbalance in gender ratio - which is leading to social problem. Also the average age of workforce has increased alot and this might hinder work and output. Hence the seniors population is increasing. This has caused a new social problem.