When Chinese officials created the country's one-child-per-couple policy in 1978, they intended to contain the country's burgeoning population for the sake of economic growth, national security and environmental preservation.
But Chinese boys now outnumber Chinese girls by the millions, and the impact of the lopsided sex imbalance is starting to spill beyond China's borders.
This phenomenon of "missing girls" has turned China into "a giant magnet" for human traffickers, who lure or kidnap women and sell them — even multiple times — into forced marriages or the commercial sex trade, says Ambassador Mark Lagon, who oversaw human rights issues at the State Department during the administration of President George W. Bush.
"The impact is obvious. It's creating a 'Wild West' sex industry in China," Mr. Lagon said.
In China, "an entire nation of women" is missing because they were aborted before they were born, said Reggie Littlejohn, founder of Women's Rights Without Frontiers, a nonprofit anti-sex slavery group. "This is gendercide."
To grasp the magnitude of the human-trafficking problem in China, it's important to have a reliable tally of the "missing girls."
Recently, the government-backed Chinese Academy of Social Services (CASS) predicted that 24 million Chinese men might not be able to find brides in 2020. However, previous estimates put that number in the 30 million to 50 million range.
In fact, a 2009 study in the BMJ (formerly known as the British Medical Journal) said that in 2005, there were 32 million extra Chinese men under the age of 20 — and that 1.1 million extra males were born in just that year.
"Sex-selective abortion accounts for almost all the excess males," said study authors Wei Xing Zhu, Li Lu and Therese Hesketh, who urged China to enforce its laws forbidding abortions based on gender.
Chinese officials plan to enforce those laws, as well as try to change Chinese "son-preferential ideologies," said a 2007 report from a Chinese academic institute. A "Care for Girls" campaign is already under way in Chinese districts that have especially large imbalances in their sex ratios, Shuzhuo Li, director of the Institute for Population and Development Studies at Xi'an Jiaotong University in China, wrote in that report.
But changing the deeply rooted "son-preference ideologies" will be very difficult.
Chinese parents believe they must have a son to carry their family name, inherit family properties, support them in their old age and host their funeral ceremonies. Tradition says children belong to their father's lineages, and daughters become part of their husband's families.
Because of these ancient beliefs, China's one-child policy forces couples to choose between "their future retirement and the lives of their daughters," said Steven Mosher, president of the Population Research Institute, a nonprofit pro-life group who has been tracking the one-child policy since the late 1980s.
Chinese officials repeatedly reaffirm the one-child policy, but also appear to be tinkering with it.
For instance, last summer, faced with a stunningly anemic 0.88 children per woman birthrate in Shanghai, officials announced that certain couples could have a second child.
But this week, the Beijing News had to back off a similar story for Beijing's couples. The paper had reported that an official with the Beijing family- planning commission said the panel was considering allowing couples to apply for a second birth permit even if only one spouse was an "only" child. Currently, both spouses must be "only" children to get a second permit.
The Beijing News report was swiftly retracted via Xinhua News Agency, a government news agency, which noted that the "journalist who wrote the original false report had already apologized" to the official. A second, unnamed Beijing family-planning official reminded Xinhua that birth-planning is "a fundamental policy" and "requires stability and continuity" to succeed.
Meanwhile, multiple alarm bells are going off about China's demographics.
The massive population is "graying," which means there will be many elderly people with far fewer workers and family members to support them.
There is also the specter of millions of young, unmarried, restless and unfettered Chinese men and how that might explode into civil unrest.
But the most immediate and horrifying consequence of China's "missing girls" is that it is fueling a growing trade in human beings, especially girls and women, say those who are fighting it.
The State Department's 2009 Trafficking in Persons (TIP) Report downgraded China to its Tier 2 "watch list," because it is a "source, transit, and destination country for men, women and children trafficked for the purposes of forced labor and sexual exploitation."
While women from many countries are being captured or trafficked into China, North Korean women are especially vulnerable. Neither China nor North Korea "seems to want to protect that population," Ambassador Luis CdeBaca, director of the State Department's Office to Monitor and Combat Trafficking in Persons, said in June when the TIP report was released.
"China's approach to human trafficking is strictly an iron-fist, law-and-order approach," said Mr. Lagon, who is now the executive director and chief executive of the Polaris Project, a nonprofit organization that fights international sex slavery.
If North Korean women protest or try to flee their forced marriages or prostitution houses, they can be "repatriated" to North Korea, said Mr. Lagon. Upon their return, they are treated like criminals and are likely to be beaten, imprisoned or killed, he said.
Laura Lederer, a former State Department official who now is part of Global Centurion, a nonprofit group fighting sex slavery, said that the sex imbalance in China is leading to a "new tsunami of demand."
"We need to be working on this on the front end," she said, calling for high-level enforcement in anti-trafficking laws.
As for the trafficking victims, Mr. Lagon urged Americans who suspect illegal activities to call the National Human Trafficking Resource Center hot line, which is operated by the Polaris Project.
Sex trafficking is a heinous human rights violation, and people may instinctively want to turn away from the issue, he said. But "it's inspiring" to see how people can escape and survive even the worst situations. "It doesn't have to be a dark subject if you are exposed to those who are fighting for dignity," he said.