A 'gift' to traffickers
Yang's son didn't come about easily - he was born after Yang's wife had three miscar-riages in six years. He named the little baby "Tianci", which means "a gift from God".
"But now he has become a gift for traffickers," Yang said furiously. His wife divorced him months after their boy disappeared.
A study by the UN this year showed child trafficking is the third most profitable crime worldwide after drug trafficking and arms smuggling.
Most of the children were trafficked from Southern China's Yunnan, Guizhou, Sichuan provinces and sold to Fujian, Guangdong, Henan, Hebei and Shandong provinces, said Zhang Baoyan, founder of Baby Come Home, which is also a volunteer group affiliated with the Ministry of Civil Affairs.
Trafficking of children is an epidemic in rural areas of Fujian Province - it is common for one village to have dozens of trafficked children, she added.
Buyers' market for boys
There is a flourishing buyers' market, especially due to the traditional Chinese preference for baby boys in rural areas.
Some rural families, fearing penalties for giving birth to more than one child, or due their inability to raise the children, sell them, which also gives rise to the abnormal black market.
Usually children are sold for between several thousand yuan to tens of thousands yuan to families wanting a child. Others are used for cheap labor as beggars, street performers, thieves, child workers and sexual services by organized criminal groups.
Lu Dongxiao, a member of the judicial committee of the people's court in Shouguang, Shandong Province, said that the high profit margin also draws many people to take up child trafficking.
"Traffickers take risks to get high profits. Most of the trafficked children are sold to poor areas," he said.
"Some families sell their children just for a few hundred or thousand yuan, however, the buyers often pay a child for tens of thousand yuan."
Lu added that the risk of trafficking is low and suspects are not easily discovered.
"It is quite easy to kidnap children. Even after the children have been rescued, they are not able to expose the kidnapper," he said.
"At the same time, the contact between buyers and sellers is cut off after the children were sold, so that it is hard for police to rescue and investigate."
"The large demand is another reason," said an unnamed official from a local legal system. Some abducted children already have registered permanent residences in the buyers' hometown so it is difficult to rescue them and punish the buyers, said an anonymous police officer.