Financial realities aside, Kellstein's film invites questions about the age of the children involved in Muay Thai and the extent to which international child labor laws and children's rights are being violated.
Kellstein says that despite the bruises, bloody noses and hard kicks to the stomach he witnessed, he doesn't feel the children are being exploited; their parents, he said, love them very much and the kids are happy to help support them.
However, groups in Thailand still object to the practice. In 1999, the Foundation for Child Rights Protection Centre in Bangkok, for example, tried to persuade the Thai government to ban child boxing. The motion failed when farmers from the provinces banded together, arguing that the farming economy would collapse if such fights were outlawed. Still, the foundation hopes a new petition to the government, scheduled for December, this year will bring child boxing to a stop, according to the organization's president, Sanpasit Kumpraphan.
Walter Mead, a senior fellow at the Council of Foreign Relations, explains that betting on child Muay Thai fights is indeed essential to the Thai economy.
"You have to understand that many of these farmers live on very narrow economic margins," he said, "and generally speaking, unfortunately in a lot of the world, poor people can't borrow money easily or cheaply. Often they have to borrow it from illegal money lenders, who charge you serious rates of interest."
Mead explained that the need for cash, after a bad crop year, is compounded in Thailand by a rabid consumerism. "More and more now in Thailand," he said, "you can start to access some of the things that you and I take for granted, like a radio or a television. … Those things take cash."
Regarding child labor, Mead stressed that in many countries it's unusual if children don't have to do serious work. "The idea that childhood is a time of play and of education is something that 200 years ago almost nobody in the world had," he said.
Is it really just Western sensibilities that make Americans shocked to see young girls punching each other without head gear as adults bet on them?
"We, Americans, we live in kind of a bubble-wrapped world and our kids live in a bubble-wrapped world," Mead said. "Life out there in much of the world has choices that we can hardly imagine. … Thailand has a very large commercial sex industry, so in that sense it's progress if girls are going to the fighting ring rather than the brothel. You have to hope that some years from now they won't be going to either one."
For his part, Kellstein said he no longer gets angry about parents allowing their children to fight. "The thing I get angry about is that there is so much inequality in the world and that economic situations like this arise," he said. "These circumstances exist and we should think of ways to make it better for everyone. Not just in Thailand, but everywhere."