According to a report by the government-backed Chinese Academy of Social Sciences (CASS), skewed gender ratio led by sex-specific abortions will pose serious problems for the 1.3 billion population in China by 2020.
More inter-generational marriages with wives being older than their husbands' will emerge due to a large proportion of men born since the 1980s, the report said.
Despite being illegal, sex-selection services for non-medical reasons are still available and affordable in China, the academy said.
"The problem is more serious in rural areas due to the lack of a social security system there," Wang Guangzhou, a researcher at the academy was quoted by the Global Times as saying.
According to the country's National Population and Family Planning Commission, a normal sex ratio at birth, or SRB, ranges from 103 to 107 males for every 100 females.
China introduced a one-child policy in 1979 and imposed restrictions on family size. It encouraged late marriages and childbearing and this is believed to have contributed to the gender imbalance.
Published 11 January 2010, 10:29 IST