China may fail to curb its worrying gender imbalance before 2015 as planned, the country's top family planning body said.

The Sixth National Population Census showed that every year, there were about 1.2 million more "leftover men" - men who are above 30 years of age and unmarried.

By 2020, China will have at least 30 million more unmarried men than women between the ages of 20 and 45.