XIAN, China -- The eerie pencil outline of Cheng Ying, drawn by her father one night last summer before she went to sleep, remains on the wall above the bed.
Her parents haven't seen the 6-year-old since they sent her off to school dressed in a black-and-white-checked coat more than two months ago. The school was no help in finding her, they said. The police weren't either, even refusing to fill out a missing person report.
As winter approached, the realization sunk in: Their daughter, the child they had sacrificed everything for, probably joined the thousands of children snatched from their parents each year in China in a burgeoning child-theft racket.
''You can see why someone would want to abduct her. She's so pretty," said her father, Cheng Zhu. ''I just hope, wherever she is, they're taking care of her."
Some of the stolen children are babes in arms. In July, 52 ring members were convicted in the southern region of Guangxi after 28 drugged and bound baby girls, none older than 3 months, were found in nylon duffel bags on a long-distance bus. One died; the rest were taken to an orphanage.
The reasons for the terrible growth industry in child trafficking are as varied as they are disturbing. In a country that earns millions of dollars a year from foreign adoptions, some children end up abroad. Others remain in the country, especially in rural China, where having a son is still seen as a must for inheritance, carrying on the family line, and tending relatives' graves. But girls also are in demand as wives in areas where men significantly outnumber women, as caregivers for older relatives, and for families that already have boys.
In the worst cases, activists and nongovernmental groups say, some are forced to work as prostitutes, maids, or in begging rings.
China often balks at releasing embarrassing statistics, including the number of its youngest citizens abducted in front of schools, on streets, and in busy markets. But specialists say the problem is growing despite repeated efforts by the government to crack down on traffickers. China has disclosed that it rescued 3,488 abducted children last year, according to the official New China News Agency. Specialists say those recovered children are only a fraction of those lost. As the Cheng case suggests, many are not even recorded.
The government has another incentive to downplay the problem: lucrative overseas adoptions. The United States and other Western countries refuse to allow adoptions involving baby-selling.
China has laws against buying babies and strict regulations to prevent children who have been purchased from entering international adoption channels. Nonetheless, the Hengyang orphanage in Hunan Province, which has provided children for US families, was caught recently buying babies.
Officials with the China Center of Adoption Affairs declined to comment, citing rules against speaking with foreign reporters, and the Ministry of Civil Affairs also declined because the case is still under investigation.
''Among the US adoptive community, there's almost a sense of freaking out over this," said Brian Stuy, an American adoption activist who heads the website Research-China.Org. ''Everyone adopts with the idea these are orphans needing a home. Even the hint they have families back in China, that baby-buying may be involved, is a big problem."
The amount of money Chinese orphanages receive for foreign adoptions -- about $3,000 per child -- far outpaces what they receive for a domestic match, creating a big incentive to obtain children legally or illegally and route them into foreign channels, according to a Research-China.Org essay on adoption finances.
Referring to the Hengyang orphanage case, the essay said, ''Given the highly lucrative nature of the international adoption program, the question is not how did this happen, but how come it hasn't happened more often."
Stealing children was virtually unthinkable 25 years ago, when communism was the prevailing ideology and neighborhood minders watched a person's every move. The headlong rush for material wealth has resulted in ''transition problems," as social mores give way to greed, specialists say.
Some children are sold willingly by their parents, in hopes they can have a son under China's one-child policy or for cash. A father in Henan was sentenced to 10 years in jail and a $600 fine in May for selling his infant son for $1,100.
Several other factors drive demand. Buying a boy and ''legalizing" the adoption with bribes often are easier than going through China's formal adoption system.