Spanking 'harms kids', says leading doctors group advising parents against corporal punishment Spanking also call ineffective in getting children to change their behavior.

When a 14-year old Texas boy stole his mom’s new BMW to go on a joyride with friends last month, his mom found him in traffic, pulled him over, and spanked him with a belt, ABC affiliate KGO-TV in San Francisco reported. The episode was caught on her daughter’s camera and started an online conversation about corporal punishment.

It's a hot topic.

The American Academy of Pediatrics has just come out with a new policy statement urging that parents avoid both "physical punishment and verbal abuse of children," citing evidence that links corporal punishment to "an increased risk of negative behavioral, cognitive, psychosocial, and emotional outcomes for children."

Corporal punishment -- defined as noninjurious, open-handed hitting with the intention of modifying child behavior -- is both ineffective for changing behavior and damaging to children and teens, the AAP said.

"In one study, young children who were spanked more than twice a month at age 3 were more aggressive at age 5," a press release accompanying the policy statement this week said. "Those same children at age 9 still exhibited negative behaviors and lower receptive vocabulary scores, according to the research."

The effects of corporal punishment as well as harsh verbal abuse can actually change a child's brain, the organization said.

"Research has shown that striking a child, yelling at or shaming them can elevate stress hormones and lead to changes in the brain's architecture. Harsh verbal abuse is also linked to mental health problems in preteens and adolescents," the release said.

The AAP urges doctors to advise parents against using corporal punishment either in a moment of anger or in a planned response to misbehavior, and to opt instead for "positive and effective parenting strategies of discipline."

“Adults caring for children [should] use healthy forms of discipline, such as positive reinforcement of appropriate behaviors, setting limits, redirecting, and setting future expectations,” the organization said.

The AAP's new policy statement "strengthens its call to ban corporal punishment," it said. In 2000, the group recommended that all states to abolish the practice of corporal punishment in schools.

This week's statement, focused on families, also seems to build on an earlier one in 1998 that recommended pediatricians "use a comprehensive approach" when advising parents and encourage the development of disciplinary "methods other than spanking."

Support of corporal punishment is generally declining in the U.S.: In 1995, 80 percent of parents reported spanking their child, which fell to 67 percent of parents in 2013, one poll found.

But in 2015, over half of U.S. adults believed it was necessary to use physical force to discipline a child. This was true across different ethnic groups as well as different regions of the country, according to a study published in the Journal of Child and Family Studies.

Since 1989, the United Nations Convention on Rights of the Child has called on all member states to ban corporal punishment, and 53 countries have done so.

But in the U.S., nineteen states still allowed corporal punishment in schools as of 2016, according to a study which also said and physical discipline was meted out to 160,000 children in the 2011-12 school year.

"I hear from many parents, 'I was hit and I turned out fine,' to which I say, 'Every developing little brain is different,'" said Dr. Edith Bracho-Sanchez, a pediatrician in California and a consultant to ABC News.

"The goal I hear from parents is a desire to teach, and when children are hit, they see themselves as the victim and automatically turn off their learning,” Bracho-Sanchez said.

"It is important for parents to remember children are always watching, so we as adults need to model the behavior we want to see in children”, Bracho-Sanchez said. "Consistent limits and consequences are also very important … For example, if the child doesn’t pick up her toys, say you will put them away for the rest of the day and actually follow through."

Repeated use of corporal punishment has been associated with increased aggression in school, and increased risk of mental health and substance abuse disorders. In one study, it was even associated with physical dating violence as adolescents, the AAP said. On a biological level, young adults who experienced significant corporal punishment actually had visible changes to the brain itself on imaging, and elevated cortisol hormone levels that are associated with toxic stress.

The AAP recommendation focuses more broadly than on just physical punishment, saying parents should avoid any disciplinary action, including verbal abuse, that shames or humiliates a child.

The group is also reminding pediatricians to advocate for effective discipline policies in their states and communities.

“I don’t think we’re getting softer," said Dr. Ryan Brown, a board-certified pediatrician and a member of the AAP's council on child abuse and neglect in a statement. "I think we’re getting smarter with our discipline.”

Dr. Tiffany Yeh completed pediatrics residency at Brown University, and is currently an endocrinology fellow at New York-Presbyterian Weill Cornell Medical Center and a member of the ABC News Medical Unit.