Hong Kong (CNN) -- China's Ministry of Public Security busted a cross-province human trafficking network last week, adding 77 children to the more than 24,000 abducted women and children authorities say were set free last year.
Police arrested 310 suspects from four gangs, two of which are family-run businesses that oversaw both the deportation and transaction of children.
Chen Qingwei, a police officer who helped crack down an infant trafficking case in Shandong, said couples who sell their babies mainly come from poverty-stricken areas, reported Global Times, a state-run newspaper.
"A boy could fetch a price as high as 50,000 yuan ($7905)," said Chen, "with the price for girls at about 30,000 yuan ($4743). This is far more than what parents could make by farming the land."
Under the one child policy and China's patriarchal society, it is common for couples to desire a boy. Chen added that most infants were purchased by families with a baby girl but still wants a boy, people who lost their children at a young age, or couples who are infertile.
Girls, on the other hand, are sold to foreign adoptive parents as "orphans." According to the Southern Metropolis News, about 80 newborn baby girls from Guizhuo were sold at a price of $3000 ($316) each in 2009.
Police suggest that gangs are using more sophisticated methods. Two gangs employed a "third ground" method to put children on the black market, police said. The first gang bought children illegally from Yunnan and Guangxi and sold them in Shandong. The second gang then received the children in Shandong and resold them on the spot to a third party, making the transaction more difficult to trace.
It is not known how many women and children in China are abducted each year.
According to the Ministry of Public Security report, the Chinese government halted 10,680 abduction cases of women and children, while busting 3,195 trafficking gangs last year. One case included 19 women forced into prostitution in Angola last year, after being deceived of a promised high-paid hotel job there.