Nearly half of the births registered between 1996 and 1999 in China were not of a first child, according to statistics released today.
Fifty-five per cent of registered births during the period were of a first child, but about 35 per cent were of a second child, according to the statistics released by the State Family Planning Commission.
About 10 per cent of registered births were of a third child or more.
China's one-child policy applied only to families in big cities, said Ms Zhao Baige, director-general of the international cooperation department of the State Family Planning Commission.
People living in rural areas were allowed to have two children, especially in the poor provinces in the west of the country, and, if the first child was a girl, even in more urbanised areas, she said.
Ms Zhao also said the trend of fewer girls being born compared to boys was not limited to China, but also experienced in other countries in Asia such as Taiwan and Korea.
The "hidden" births of girls, whose births were not registered, also explained the imbalance of 117 boys for every 100 girls, she said.
She said the detection of the sex of a child during pregnancy was illegal. Ms Zhao also acknowledged boy babies were given more attention than girl babies.
In rural China, parents rely on their sons to provide for them in their old age, as their daughters live with the families of their husbands.
AFP