For years in America we've debated how young is too young to push kids -- serious athletics but the story we're gonna bring you tonight takes that debate to an entirely new level. These are parents... See More
For years in America we've debated how young is too young to push kids -- serious athletics but the story we're gonna bring you tonight takes that debate to an entirely new level. These are parents who believe that their kids character can be forged by doing battle in the ring. At age seven here's ABC's Neal Karlinsky. These seven to nine year -- are getting ready for their big night even at this young -- they've been training for years. It's 7 o'clock in Thailand -- a school night and hundreds of come here to watch these children. Beat the living daylights out of each other. No -- mouth guards or any other form of protection this is that Thai version of Friday Night Lights. But far more dangerous -- action nearly every night of the week. The kids including girls. Have been captured on video during some unspeakable -- disturbing moments a child growing up in the ring crying wanting to quit. And being sent back in. Watch this little girls eyes doctors tell us she is having a seizure from blows she suffered. To find out what's going on here Nightline traveled from the streets of Bangkok out to the Thai countryside. In a village called clutching buried we find it tiny stone -- seven year old named beauty preparing for his first fight. Asking these -- -- question most parents wonder right about now aren't you worried about it getting hurt. I'm not scared she says because I want to teach -- to be tough and he says he likes to fight. Because I get the money he says. We're a little nervous for Randy is he's paraded into the ring. He's fight. Doesn't last long the refs call and offer relief fearing that he's out matched this man is the fight organizer you could never get hurt. The fights are not that dangerous he says because the gloves help protect them -- because they're still small. Sears where it gets even stranger this is not some secret back room sport but virtually -- national pastime. Legally among the poor. You can find a fight any night of the week in the province and Todd -- -- spent years inside Thailand's child boxing culture for his film buffalo girls. The movie follows the lives of two young girls whose families rely and then to win in the ring. For money. Mainly in the form of the widespread gambling that goes along with the child fights. The betting is -- definitely what drives the whole thing both the love of the sport but it's also the -- -- trainers. The promoters -- his family's all bets on the fights and they all Mika. Pretty good money doing that. Nine year old -- -- in his typical of many of the fighters we met. School by day. Then crammed into the back of a truck for the bumpy ride home. Where there was a makeshift boxing ring built atop a crumbling old dock along -- river. She has fifteen Brothers and sisters -- And they fight. How many fights have you had and how many have you -- -- -- -- Eleven fights and I -- all of them she says where -- -- people think it's not safe. For a little kids like you to fight. -- hung on one Hamas. Don't worry thirteen year old -- says we're so well prepared we don't get heard that training is endless jogging every day. Exercising and drilling repeatedly. Even the smallest are expected to join in not surprisingly at this point the father of former fighter -- -- tells us. He has no safety concerns -- all. -- -- -- -- up and doing they're proud mother shows off the families overflowing stash of trophies and prizes. There are some mothers -- watch this who say. It's your job to protect them having a seven year old in the ring no protection. It's dangerous. -- -- -- -- -- It's as sports and there are bigger problem she says adding that he keeps the kids happy and focused and away from drugs. In Thailand where this form of boxing and has more -- -- is fully in -- in the culture. Researchers estimate 100000. Kids under sixteen -- actively fighting -- kids are already showing evidence that memory damage. -- that that it could bring. Doctor G report -- -- -- may be tackling the biggest fight. She's part of a team in Bangkok -- the first ever research into what all this fighting is doing to the children like conducting brain scans and other tests on 100 child boxers. She says early tests are far worse than she imagined when she began the project their brains look like people -- been an automobile accident. Yes the data is revealing child boxers have much better eye hand coordination and other kids from intense training. But they also have serious memory issues that will grow worse one of the kids being tested his ten year old -- -- Like others we met she too is part of a fighting family and her father set up this makeshift boxing ring next to the police station where he works the family also like the others -- poor. -- such -- -- that tiny apartment with Brothers and sisters and there were hopes that her fighting skills will be her ticket out. From what we saw she is -- Focused and unbelievably -- in the -- She is fierce in there and throw some really hard punches she must also get hit pretty hard do you ever worry about -- I was very scared she says but after seeing her in practice in the fact that she learned how to protect herself and I feel better. The family believes fighting keeps the kids away from other dangers. And that is the trouble with these troubling sport magazine -- in a culture that provides few alternatives some of these kids would be working in sweatshops or worse. But to working Bangkok's infamous red light district if they weren't in the ring. If something I've struggled with quite a bit during the shooting and especially during the editing process. I went there with very western centric idea. -- it took me a lot of time to realize that this is a way of life in these kids are putting their. Brothers and sisters to school buying uniforms -- pens pencils one of the kids in the film built to house their parents. And so disturbing as the early research is it may not make a difference in -- culture and not yet ready to accurate. And -- prepared to offer -- better way out. -- Neal Karlinsky for Nightline. In Bangkok Thailand.
This transcript has been automatically generated and may not be 100% accurate.