Zhang Yantao shows a coat his missing Vietnamese 'bride' left at home in Zhuzhuang village, Handan, North China's Hebei province, Dec 12. [Photo/CFP]

The Beijing Times, quoting Wang Zehua, a researcher at Hebei Academy of Social Sciences, said that with increased urbanization growing numbers of young rural women move to cities through marriage.

Although many rural men flock into cities for a job, the high cost of marrying a woman there outweighs the money they earn, making it difficult to build a new family. As a result, they are forced to return to their villages. Anomalies in female and male rural populations leads to a serious imbalance between the sexes, said Wang.

Despite uneven economic development between rural and urban areas, the deep-rooted Chinese concept concerning reproduction is a widely discussed cultural aspect contributing to the worsening situation.

The preference for male offspring has long dominated mainstream culture. Conservatives, especially old-fashioned clans in rural areas, regard boys as the only recognized heirs to carry on a family line.

According to figures released by China's National Bureau of Statistics in January last year, men outnumbered women by 33.8 million in a country of more than 1.3 billion population.

For every 117.6 boys born there were 100 girls (the natural rate is 103 to 106 boys to every 100 girls), a government report showed in 2013.

The huge gap between sexes forces "leftover" men, particularly financially constrained rural ones, to look across the border for an "economic" bride, although this poses potential dangers.