Despite an alarming sex ratio among newborns in some parts of the country, the overall sex ratio of the younger population in China is "generally normal", a national report concluded.

The report, released by the China Youth and Children Research Center and Beijing's Renmin University of China, said the sex ratio, which refers to the proportion of males to female, for the country's total youth population had fluctuated around a range of 99 to 105 and reflected "a slowly downward tendency" since 2000.

It indicated that the sex ratio of the population aged 14 to 29 had declined from 105.7 in 2000 to 100.2 in 2005. During those years, the ratio for persons aged 14 to 35 had dropped from 105 to 99.2.

Liu Junyan, who was in charge of the report -- which was based on the national census sample carried out on 1 percent of the total population in 2005 -- said that those who were young in 2005 were born in the 1970s and 1980s, at a time when the sex ratio for newborns was "relatively normal".

However, the report indicated a dramatic increase in the sex ratio for the rural youth population, in comparison with the sex ratio for urban youth, which decreased over the five-year period.

Liu said with tightening family planning policies since 1980, rural areas showed a stronger preference for boys in line with the traditional belief that boys could carry forward the family bloodline.

"Before the family planning policy was implemented in 1979, people would have more children to increase the chance of having boys, which was a natural selection that did not damage a balanced biological development by sex," he said.

After the state policy, which encouraged families to have only one child, took effect, some Chinese still had more babies until a boy was born. They would simply defy the law and pay fines, Li said, adding that this situation still could not affect the sex ratio.

Serious gender imbalances occurred after the late 1980s when the B-ultrasound technologies used for sex-selection were widely available in China. More Chinese chose to abort female fetuses after mothers underwent such a test.

Statistics show the sex ratio for newborns was 119 boys to 100 girls and the figure was more alarming in provinces such as Jiangxi, Guangdong, Anhui and Henan, where it stands as high as 130 in some areas.

Although sex-selection for non-medical purposes is banned under the Population and Family Planning Law and the Law on Maternal and Infant Health, there are currently no provisions for breaking the laws.

Currently the State Council, or cabinet, is working on a regulation to ban illegal selective abortion to combat the rising gender imbalance.

China's male population currently outnumbers that of females by 37 million, the most uneven in the world.

Zhang Weiqing, National Population and Family Planning Commission director, said that by 2020, males aged between 20 and 45 are forecast to outnumber females by 30 million.

The report also pointed out that gender imbalance would give rise to an increase of unmarried young people, with more males than females staying single, which, observers believe, will be a social timebomb in the years to come.

"It will become more difficult for low-income males to find suitable spouses as they get older, and they will cause social problems," the report said.

The country's family planning policy had helped China to reduce the speed of its population growth, delaying by four years the 1.3 billion figure reached at the beginning of 2005.

However, the traditional idea that more children bring more happiness and more helpful hands in agricultural production prevails in rural areas, challenging the country's population control efforts.