RUILI, China — Her bleak, concrete-walled room is first in a row down a dark alley, behind a small shop selling water, cold teas and sample packets of shampoo. Inside the bare room lit by a single fluorescent tube, the prostitute sits atop a hard single bed, dressed in deep blue and gold. Her long hair cascades down her back; her face is painted carefully.

She is 19, and only agreed to meet if we protected her identity. In another life, she might be a university student or a farm girl. Here, she is a prostitute servicing Chinese men in a drug-riddled city on the China-Myanmar border.

There’s a knock at the door. It’s another young woman from Myanmar (formerly Burma), hurriedly pulling a stack of cash from her bra and handing it to the young woman. “Keep this,” she says. “The gangsters are outside tonight looking for money.”

The panicked interruption is routine.

Gangsters are never far; there is no protection by police, the women say. The young woman tucks the cash into her top and continues talking. She tells of crossing the border into China at 16 to work as a cleaning maid. She was, she says, tricked into prostitution, working on the streets. She moved up because she was good looking.

She’s now a “mommy,” in charge of handling arrangements for other Myanmar prostitutes in this neighborhood. She accepts a limited number of her own clients, but wants desperately to be seen as in charge of her own affairs.

The money she earns goes home to her family, to educate her brothers in Mandalay. While she was tricked into this life, she says, she’s accepted it. Her family, she insists, must not know how she earns the money she sends home.

At this point, her visitors are rushed from the room. A customer is on his way.

The truth she can’t tell emerges later. Her own mother sold her into prostitution in China. Her fate rests on surviving this dangerous world. Whether she will ever go home and realize her dream of building a new farmhouse for her family depends on her ability to survive the wretched underbelly of a Chinese border town.

Stories like hers play out over and again in Ruili, this small Chinese city 10 miles from a permeable border with Myanmar. It’s the start of China’s heroin trafficking route, where HIV/AIDS first entered the country in 1989. Smuggling is routine at all hours. Traders who don’t want to cross the official border checkpoints and pay taxes simply boat across a few miles downstream, where police are more amenable to looking the other way.

Over this border, everything moves with practiced ease. Mundane goods like food, clothing and cooking oil slip back and forth. But also illicit items like guns and drugs.

With the rise in the number of single Chinese men in the past decade, demand has grown for one particular Myanmar import: women. Some come willingly, others are tricked and traded, and some don’t even know they’ve crossed an international border. Many are children.

One Myanmar aid group says known trafficking cases — mostly bought brides — quadrupled from 2008 to 2009. Though aid groups detail the increase, neither they nor the Chinese government can provide firm numbers.

At least 10,000 women from Myanmar live and work in the Ruili area, with varying degrees of legal status. Many are maids and nannies. Many more work in the sex trade. This is a hub of prostitution, and foreign women are both exotic — a big draw for Chinese men — and cheaper than Chinese girls. Prostitution halls are often disguised as massage parlors, but the sex trade is barely hidden.

Women lured from Myanmar to China fill a gap created by this country’s one-child policy and cultural preference for sons. By 2020, an estimated 35 million Chinese men will be unable to find wives. Increasingly, bachelors buy women from poorer countries like Myanmar and North Korea.

The Chinese government has stood firm to its single-child policy, but government-linked sociologists have begun to publicly question its impact. Though the policy appears to be holding fast, demographers say it’s clear that change is needed.

“The situation has created a very cheap and very strong marriage market,” said Wang Yi, a sociologist and population researcher at the Chinese Academy of Social Sciences.

While prostitutes live on the fringe, working illegally, many quasi-legal brides fare better.

The countryside around Ruili is dotted with small villages where dozens of the women have come from Myanmar. The going price for a bride “in top condition” is 50,000 yuan ($7,300).

An hour from Ruili, in Nongbie village, more than half the wives of the 100 or so families are from Myanmar. Those willing to talk insist they came to China freely.

Han Rui, the mayor’s wife, discussed inter-cultural marriage in her living room as her son studied Chinese characters. With a baby on her lap, she spoke about cross-border marriage as an arrangement that benefits everyone. Though she wouldn’t acknowledge a shortage of local Chinese women, she and the other women in town laugh when asked how they met their husbands — most of whom are ethnic Dai, closer to the people of Myanmar culturally than Han Chinese.

“Oh, we just met,” one woman says. “At a festival,” another chimes in, giggling.

Bride brokers work openly in these parts. But because the business is unregulated, horror stories happen. Women have been beaten and killed by their Chinese husbands. The local Burmese women’s federation recounts a harrowing tale: A woman sold to an elderly Chinese husband escaped his home and made her way to the local police station. Because she spoke no Chinese, the police could not understand her problem. They sent her home to virtual imprisonment.

Trafficking of women and girls is not confined to the border. Further west in Yunnan province, women and girls are smuggled in from Vietnam and Laos. The problem stretches across China’s vast borders. International anti-trafficking agencies say women are brought to China from Russia, Mongolia and the Ukraine. Women from the poorest countries are most at risk, and the problem worsens on China’s border with North Korea — particularly because North Korean women are sent back to their home country to face disastrous consequences when caught.

In an odd illustration of China’s place as both a developing country and economic power, aid groups say China’s human trafficking problem is multi-faceted. Even as the country imports thousands of women and girls, poor Chinese women still are trafficked to other countries. In addition, Southeast Asian women are trafficked through China to places like Thailand.

In its 2010 report on human trafficking, the U.S. State Department calls China a second-tier threat, in part for its failure to provide data and comply with international agreements. The report, released in June, faults in part China’s gender imbalance.

“During the year, there was a significant increase in the reported number of Vietnamese and Burmese citizens trafficked in China,” the State Department said. “Some trafficking victims are kept locked up, and many of them are subjected to debt bondage. Many North Koreans who enter into China are subjected to forced prostitution or forced labor in forced marriages or in internet sex businesses.”

Officially, China has intensified efforts to combat cross-border trafficking, but aid agencies say the problem is growing. As the shortage of Chinese women grows, the outlook is bleak.

“Some experts and NGOs suggested trafficking in persons has been fueled by economic disparity and the effects of population planning policies, and that a shortage of marriageable women fuels the demand for abducted women, especially in rural areas,” the U.S. State Department said. “While it is difficult to determine if the PRC’s male-female birth ratio imbalance, with more males than females, is currently affecting trafficking of women for brides, some experts believe that it has already or may become a contributing factor.”

Talk of policy and programs means little to the women and girls sold into China. For them, survival is a priority and dreams are in short supply.