SHANGHAI: Expectant Chinese parents are for the first time more likely to hope their offspring will be a daughter rather than a son, turning their backs on decades of tradition.

China’s one-child policy has produced a calamitous glut of men, but an increasing number of families are now hoping their only child is a girl. The country has 32 million more young men than women, a situation that is already leading to an increase in prostitution and sex crimes.

But in its enormous cities, the high cost of raising a son has meant that for many families, daughters now make more economic sense.

In Shanghai, government researchers questioned about 3500 prospective parents. Of those, more than 12 per cent said they were hoping for a boy, while more than 15 per cent wanted a girl.

Reversing the traditional preference for sons is a crucial issue for the Communist Party, which is dealing with the consequences of having millions of unmarried men. Latest figures show 120 boys are born for every 100 girls.

Sons are seen as more valuable, especially in the countryside, because they have been traditionally responsible for caring for their parents in old age.

However, the traditional roles are being reversed in urban China, where ‘‘city residents are covered by social security’’, said Chen Youhua, a demography and sociology professor at Nanjing University.

The rising cost of living has also diminished the appeal of male children. In most marriages the son’s family is required to buy a house for the couple – a ruinous expense in many cities where property prices rose by as much as 60 per cent between 2007 and 2008.

Li Qian, 27, a secretary in a private bank, said the economic crisis had left parents with sons having to provide for two families, their own and their children’s. ‘‘Many would-be parents want to have daughters to reduce their financial burden. Girls can marry rich husbands.’’

Zheng Zizhen, the director of the Institute of Sociology and Population at the Guangdong Academy of Social Science, said families were already more pragmatic about dowries and house purchases.

‘‘As China develops, traditional practices will fade away. When that happens, there will be a preference for daughters generally, because it is the women that stand by the bed and care for you in old age, not the men.’’