Certainly poverty plays a critical role in motivating poor girls and women to seek employment in far away places, as well as generating a market for the sale of women to brothels. But what is driving the increase in demand for illicit sex?

In an article in the Journal of Sexual Aggression, Hughes said, "In the last three decades, prostitution and pornography have become increasingly tolerated, normalized and legitimized, resulting in expansion of sex industries all over the world."

This tolerance, she said, has "increased men's demand for women and girls to be used as sexual entertainment or acts of violence. The demand is met by increased recruitment of women and girls into the sex industry, usually by violence, deception or exploitation of those made vulnerable by poverty, unemployment and prior victimization."

The Internet has made pornography ubiquitous, and Hughes said this new forum has "provided pornographers access to a global audience with almost no restrictions or regulations. It provided men, who are usually secretive about their exploitation of women and children, with easy, private access to unlimited amounts of pornography."

The country that comes in for the lion's share of the blame is the United States. Hughes said, "The U.S. is the country mainly responsible for the industrialization of pornography and prostitution, either in the U.S. or in prostitution centers created by the demand from U.S. military personnel. The U.S. is also the home of the Internet pornography industry."

For example, Hughes said that, according to one study, 70% of the customers for live sex shows on the Internet are in the U.S.

American Taste for Trafficked Girls

Virtual sex is not the only decadent delicacy for some Americans; the simple fact is that thousands of trafficked women and girls are ferried into the U.S. for the purpose of illicit sexual encounters.

In an article for The Weekly Standard, Hughes wrote about the extent of the sex trafficking industry that shuttles girls through Mexico to brothels outside San Diego, California. "Over a 10-year period, hundreds of girls, 12 to 18 years old," were brought into the U.S. by Mexican nationals.

"The girls were sold to farm workers -- between 100 and 300 at a time -- in small 'caves' made of reeds in the fields. Many of the girls had babies, who were used as hostages with death threats against them, so their mothers would not try to escape," Hughes said.

An American doctor who was volunteering to provide health care to migrant workers in the area told Hughes that younger and younger girls were brought over the border -- some nine and 10 years old -- who might be used by as many as 35 men in one hour. "The first time I went to the camps I didn't vomit only because I had nothing in my stomach," the doctor told her. "It was truly grotesque and unimaginable."

When she wanted to complain to government authorities about the abuse, the doctor was instructed by her supervisor to concern herself only with trying to prevent the girls from contracting sexually transmitted diseases by providing condoms.

"I fought a lot with the U.S. government and they told me that I shouldn't do anything, that I had signed a federal agreement of confidentiality," the doctor said.

From San Diego to New York City, girls and women are being abused in the middle of normal neighborhoods, "hiding in plain sight," according to Hughes.

It is a staggering vice, and Landesman said the U.S. has become "a major importer of sex slaves. Last year the C.I.A. estimated that between 18,000 and 20,000 people are trafficked annually into the United States." Of these, an estimated 10,000 are victims of the sex slave industry.

Those numbers add up. According to Kevin Bales, author of the book, Disposable People: New Slavery in the Global Economy, and president of Free the Slaves, America's largest anti-slavery organization, there are 30,000 to 50,000 sex slaves residing -- against their will -- in the U.S. at any given time.

Cracking Down