The skewed sex ratio may result in a growing army of what are becoming known as 'surplus' men, especially in poor rural areas.
Census figures revealed that in 2010, 118.06 boys were born on the mainland for every 100 girls.
That compares with 116.86 in 2000, which experts said was already too high. But the 2010 figure was down from the 119.45 boys for every 100 girls born in 2009, Ma Jiantang, director of the National Bureau of Statistics, said yesterday.
The normal ratio based on physiological rules was between 103 and 107, Ma Li, former director of the China Population and Development Studies Centre, said.
The imbalance could mean more difficulty in finding wives for men in remote, poor areas, Ma Li said. 'The less competitive men in cities may find wives in rural areas; those in rural areas may turn to women in poorer villages or border areas; and the leftover men in these places may either be left single or buy women from neighbouring countries, such as Vietnam, which we have heard a lot about in recent years,' she said.
Professor Yuan Xin of Tianjin's Nankai University blamed the imbalance on parents' persistent preference for boys.