Many of the products sold at Victoria's Secret are said to contain 'fair-trade' cotton. But a new report from Bloomberg News found that that cotton is often planted and picked by children 13 and younger, who are forced to work like slaves.

Fair trade cotton is an increasingly popular material in clothes sold at upscale, trendy retailers.

Take Victoria's Secret, for example. Many of their panties and bras are made only using "certified" fair trade cotton. But there's no official definition for what fair trade even means.

But it certainly doesn't mean children as young as 13 being forced to work in cotton fields and being beaten. And that's exactly what a Bloomberg reporter found after spending six weeks in Burkina Faso.

Cam Simpson is the Bloomberg News reporter who went to Burkina Faso, where he found many children working in slave-like conditions. Clarisse Kambire, a 13-year-old foster child, was among them.

See a photo gallery from the cotton farms at hereandnow.org.

"These are kids often who are abandoned, children of unwed mothers, sometimes. Quite often, they're children who are sought for their labor," Simpson said. "What we found was when you overlay incentives for, small farms, to make big money from fair trade products, like fair trade cotton, it created an incentive for people to get into this business and use these kids to do the work."

Buying ethically sourced products, from cotton to coffee, is becoming big business because it's good business.

A recent study found that just putting a fair trade label on a bag of coffee increased sales 10 percent, Simpson said. When he talked to Victoria's Secret, he said he got the impression the company believed they were buying fair trade products and felt let down by their vendors.

"This is big business. And it's big business for major corporations and it's big business for the fair trade movement," Simpson said.

According to Simpson, this existence is what Clarisse expected as a foster child.

"The National Farmer's Union, which runs this program for Victoria's Secret, cosponsored a study in 2008, that was never published, in which they found there was an average of one of the foster children on each farm across the country," Simpson said.

The study said they were extremely vulnerable to exploitation. During the rainy season, Clarisse, had to dig a field the length of four football fields with nothing but her own strength and a hoe. Simpson said this is typical of what is asked of these foster children.

In most developing countries, this work would be done by an animal and a plow, but in Burkina Faso, farmers are so poor it's easier and cheaper to use orphans.

"It's really extraordinary. The work goes on for six or seven months, all the way through the harvest," Simpson said.

And because the cotton is organic, the work is perhaps even harder. Clarisse must weed the fields by hand, haul manure compost to each of the plants and pluck worms out of the cotton, and then smash them with her foot.

"It's organic, it's pure, but that comes with a price for Clarisse and kids like her," Simpson said.

Victoria's Secret told Bloomberg that it was going to investigate the claims, though it noted it gets just a small portion of its cotton from Burkina Faso.

“They describe behavior contrary to our companyΆs values and the code of labor and sourcing standards we require all of our suppliers to meet,” Tammy Roberts Myers, vice president of external communications for Limited Brands Inc., said in a statement to Bloomberg. VictoriaΆs Secret is part of Limited.

“Our standards specifically prohibit child labor,” she said. “We are vigorously engaging with stakeholders to fully investigate this matter."

According to the U.S. Department of Labor, cotton is produced using child labor more often than any other commodity, except gold.