A mobile app helped Chinese authorities recover hundreds of missing children last year

Child trafficking is common in China, where population control policies, although recently relaxed, have bolstered a traditional bias for male offspring.

Boys are seen as the main support for elderly parents and heirs to the family name. This has resulted in abortions, killings or abandonment of girls.

The Ministry of Public Security said 611 missing children were found last year, Xinhua said.