China's more than 100 million women aged between 20 and 29 posed an enormous threat to the Government's population plan, according to a State Statistical Bureau report.
The report identified the main threats to the bid to control population growth.
The women of child-bearing age would be the 'core targets' of the Government's birth control programme in the next five years, it said.
The report also identified a vast sexual imbalance among newborn babies in the countryside. It quoted a 12-month survey in October 1994 to show that the ratio of newborn baby boys to girls in villages was as high as 117 to one.
It said the practice of farmers using ultra-sound detectors to examine the foetus and abort the babies if they were girls was still common in the countryside.
The bureau said many villages did not report births to the authorities. The migration of rural labourers to the cities had hampered birth control efforts.
According to incomplete statistics collected, about 40 to 50 million people moved between villages and cities every year and such a high floating population had made it more difficult for the Government to monitor and control the problem. The bureau believed the total population would reach 1.3 billion by 2000 if the net birth rate was controlled at 2.5 per cent. Last year, the net birth rate was only 1.8 per cent.