Graph Showing Age by Gender
1990 Census - China

China imposed strict population controls in the 1970s to limit growth of its huge population, but one side effect has been a jump in gender selection of babies. Traditional preferences for a son mean some women abort their baby if an early term sonogram shows it is a girl.

"Discrimination against the female sex remains the primary cause of China's growing gender imbalance," Liu Bohong, vice director of the women studies institute under the All-China Women's Federation, was quoted as saying in a report from the State Population and Family Planning Commission.