"Ultimate fighting," the controversial sport that combines martial arts, wrestling and boxing, is now attracting children as young as 6 years old.
The popular form of fighting, which has few rules and often takes place in a cage, has been described by Sen. John McCain as "human cockfighting."
Some parents say they're signing up their children to help with self-defense, discipline and confidence. Some are even training their little ones now hoping to go pro. But with violent grown-ups as their role models, many people are shaking their heads.
Though most professionals admit it's a sport that requires years of training, kids as young as 6 can now be seen on YouTube punching, kicking and pummeling each other, mimicking their Ultimate Fighting Championship heroes. So far the children's version is only legal in Missouri.
Jennifer Swinehearts' sons, 10-year-old Hayden and 14-year-old Larry, are members of the controlled "Garage Boys Fight Crew" in Joplin, Mo. Even their 12-year-old sister, Shelby, is in on the action.
"It's wonderful. They build such good character and good friendships, and that's what you need to further yourself in life," said Swinehearts.
The children fight in small cages but are required to wear head gear and padding. The no-holds-barred fights without protection aren't allowed until they turn 18.
"I daydream during school of me being in the cage with everybody watching me on TV," said Larry Swinehearts Jr.
Experts say the pint-size version of the sport is growing because ultimate fighting is everywhere now, on cable television, pay-per-view, even on the big screen in the movie "Never Back Down."
The sport is undeniably dangerous for adult fighters facing brain damage, broken bones and even death. Doctors say they're now starting to see injuries in young fighters that can impact their growth.
"I think it's dangerous from a physical standpoint," said Dr. Lisa Thorton, a pediatrician with the University of Chicago Hospitals. "It can make significant injuries to the neck and bones, and if they're being taught that fighting is a way to solve problems that is obviously very negative for any child."
Swinehearts believes ultimate fighting for children, done the right way, is safer than football. She admits the adult violence scares her, but she knows her children will benefit from starting so young.
"They do want to be champions. They work very hard and that is what they see as the ultimate goal. They want to be the best of the best," she said.