WHEN Li Xiang Xiang, aged 2½, went out of her family's home on April 1 to the shop around the corner, as she did every day, her mother expected to see her back in minutes with a big smile and a bag of sweets.

Instead, Xiang Xiang - whose rhyming name means “thoughtful” - vanished and her heartbroken mother and father joined the ranks of Chinese parents who fear they have lost their little girls to child kidnappers.

Small boys have long been abducted for sale in China, but in recent years the country’s strict birth control policy, which has led to abortions of girls in families intent on having a boy, has left the countryside short of female babies.

According to a recent report in the British Medical Journal, 124 boys are born for every 100 girls in the country as a whole, and in one province the figure has risen to 192.

Stolen girls have therefore become increasingly valuable commodities in an cruel trade. Many are bought by farmers who want wives for their small sons when they come of age or by men who want a child bride without a dowry, say police and the state media.

The public security ministry says that between 2,000 and 3,000 children and young women are kidnapped every year, but the state-controlled newspapers have put the figure as high as 20,000. Only a handful of cases are solved.

“I can’t eat. My wife cries every night. Our son, who’s one, has been sick since his sister vanished and now he’s in hospital,” said Xiang Xiang's father, Li Faming, 35, who sat wringing his hands and smoking in a backstreet cafe.

He and his wife were permitted a second child because their first was a daughter.

His pain testified to the emotional bond that many young Chinese fathers develop with their girls, in contrast with an older generation for whom sons were a prize and daughters a burden.

His story is typical. He makes just enough money as a decorator to survive in Shuang-qiao, a slum district on the fringe of Kunming, the capital of Yunnan. The province, in southwestern China, is a centre of human trafficking that is spreading to Burma, Laos and Vietnam.

“We went to the police and they took a report,” he said. He produced the tattered, precious piece of paper – which, it turns out, few such parents receive.

“They said they would investigate. When we went back, they said they’d been to ask questions but our neighbours never saw them. This morning they said they were too busy to see me.”

Impoverished and powerless, the family made their own “missing” posters with carefully printed appeals, a photograph of Xiang Xiang, the offer of a £6,000 reward - although it was not clear how they ever hoped to amass so much money - and their telephone numbers.

Friends and neighbours helped to plaster the notices around the district where, Li says, about 10 children have gone missing since March alone.

Two things happened. A hoaxer telephoned Li to try to extort money, so he alerted the police and went to a meeting with two undercover officers, who arrested the man. Then the police tore down the posters.

“That happens all the time,” said another father of a missing child whose attempt to launch a campaign has resulted in police surveillance and harassment. “They don’t want the city to have a bad image.”

It was impossible to offer Li much comfort in his misery.

The kind of media and police attention accorded to missing children in developed countries and epitomised by the case of Madeleine McCann is unimaginable in China.

Take Mao Yinjie, aged four, another girl who has been missing for more than a year.

Her disappearance led to local press and television coverage but only after her father, Mao Zhengfa, 37, who with his wife sifts rubbish for a living, got fed up with police inaction and called a hotline to the mayor’s office.

Yinjie - “the pure nightingale” - was left to play with a group of children outside the family’s home while her parents juggled their hours of work.

Frantic after losing track of her, they went to the police while neighbours organised search parties. A thousand posters were put up appealing for news, although most were later torn down.

The parents’ anguish was compounded when security guards showed them a video recording of Yinjie leaving the other children and heading out of a courtyard.

“She stopped and looked back three times and then she walked out onto the road,” said her father, who could not keep the trembling out of his voice.

Yinjie’s mother felt suicidal at first and collapsed in bed for weeks at a time. It drove her father to pester the local media for help. “They weren’t interested,” he said.

In despair he called the mayoral hotline and connected with one of those fleeting moments in China when a citizen’s need coincides with political convenience.

The next day a television reporter and crew called on him. City newspapers printed stories. The police put Yinjie on a list of missing persons and interviewed witnesses.

“More than a year later there’s nothing,” said her father, “but I’m not giving up.”

Parents across China have defied the authorities’ instinctive repression of any mass campaign by signing up to a website whose name means “baby come home”.

No fewer than 2,000 sets of parents have posted details of their missing children. Four hundred children have also registered to look for their families. But the site has claimed only seven successes in two years.

The Chinese government accepts that child abductions are growing.

“More children are being kidnapped by criminal gangs,” said Yuan Xiaoyin, a ministry official in Yunnan, vowing a tougher response.

Last month the public security ministry mounted its sixth campaign against the trade and issued a list of the country’s 10 most wanted human traffickers. It also launched a nation-wide DNA database to help resolve identification of missing children.

Reliable data on the number of girls being snatched remain as hard to verify as every other crime statistic in a country of 1.3 billion people. But the police, state media, experts and parents all say the figures are going up.

“I have heard reports from Chinese sources that such abductions are increasing,” said Valerie Hudson, of Brigham Young University in the United States, who has studied gender ratios at birth in China. “But [the] abduction of toddlers takes things to a whole new level and certainly indicates, as the data plainly show, that the sex ratio problem among the youngest cohorts of the Chinese population is increasing, not decreasing.

“It makes me wonder if the traffickers have sensed a lucrative new market and seized upon it.”

In raids over the past month, police have freed 51 girls from kidnappers, according to official media reports. This is a complex criminal challenge.

Police who raided one village in Guangnan county in southern Yunnan found that babies were being raised for sale and families were acting as brokers for other peasants who wanted to sell off “surplus” infants.

However, the abduction of very young children who may not even understand that they have been wrongly taken demands different methods from those used by detectives investigating the kidnapping of girls for China’s booming sex industry.

The difficulty of fighting the crime has led campaigners to demand harsh measures against the people who keep it going, the child buyers.

“They are at the root of the problem,” said Zhang Baoyan, director of the baby-come-home website, in an interview with the China Daily.

The newspaper endorsed her call for tougher penalties, calling the current maximum sentence of three years in prison “by no means heavy enough”.

It would be hard to think ofa punishment stern enough to compensate the distraught fathers of Kunming, who carry their missing daughters’ photographs close to their hearts every day.

Additional reporting: Richard Jones

Times Recommends

• No apology for Germany’s own Nazi victims
• Intricate web of fear and hope tying down deal
• Victims remembered a year after Mumbai attacks