A study carried out by Lund University sociologist Lisa Eklund has shown the China's "Care for Girls" campaign, doing more harm than good.
Under the campaign, the government provided extra support to families having girls and, made exceptions where the first child was a girl in a rural family.
"By compensating parents of girls in various ways, the government reinforces the idea that girls are not as valuable as boys", Eklund said.
Giving reasons for the Chinese preference for a male child, Eklund said: "One important reason that families in rural areas want sons is that they are expected to take over the farming. Although that is a poor argument. Young people, both men and women, are moving away from rural areas. Of those who stay, women provide just as much help as men. In fact, it is the elderly who end up taking greater responsibility for the agriculture."
She said there are also other reasons why sons are seen as more important for families. It is traditional for a girl to move in with her husband's family when she gets married and she thus cannot look after her own parents when they grow old. Boys also play an important role in ancestor worship.
Her study has also provided the answer as to why the families in cities want a male child at any cost.
From the 1990s, the number of families who wanted to have a son at any cost have doubled (from 2.8 per cent to 4.5 per cent).
"This doubling came at the same time as cuts in the state welfare system in the cities, which meant that adult sons were given a more important role in providing for the social and financial security of the elderly", she said.