(CNN) -- Ian Swanson was 5 when his family moved from the United States to Umeå, a small university town in northern Sweden. It was the place where he made his first friends, where he learned to read and where, like any kid, he was "into absolutely everything."
He occasionally got a spanking from mom, or a swat on the rear and a stern look from his dad. But he remembers one day when his kindergarten teacher, school principal and a social worker came to their home. They worried Ian wasn't fitting in; they wanted to talk about the "abuse."
Swanson remembers translating for his parents, who were still learning the language, too: "'You have to understand, things are different here.'"
In 1979, a few years before the Swanson family arrived, Sweden became the first country to ban physical punishment of children.
Since then, 30 more countries have passed bans on corporal punishment at home, and even more have banned it in schools, according to the Global Initiative to End All Corporal Punishment of Children. Just last month, Togo confirmed to the United Nations Committee on the Rights of the Child that parts of its children's code are meant to ban physical punishment.
No countries in North America ban physical punishment by parents, but there's a perennial debate about the line between discipline and abuse, and who's allowed to administer it. It flared again last week after millions watched a seven-minute YouTube video from 2004 that showed a Texas judge cursing at his teen daughter and beating her with a belt.
While there are laws against child abuse, it's legal in all 50 states for parents to hit their children, and for schools in 19 states to physically punish kids. About 80% of American parents said they've hit their young children, and about 100,000 kids are paddled in U.S. schools every year, researchers said.
Kids are still hit with hands, belts, switches and paddles, said Elizabeth Gershoff , an associate professor of human development and family sciences at University of Texas, despite research that shows it doesn't model or teach behavior parents are looking for, that it damages trust between parent and children and that it can lead to increased aggression.
Although more parents are trying a variety of disciplinary measures, corporal punishment isn't going away, and some researchers argue that it shouldn't. It's effective for gaining immediate compliance from young children, and is unlikely to have long-term negative effects, they said. More powerfully, it's hard to stop a discipline technique that's been passed down through generations.
"There hasn't been a sea change in attitude. Most Americans still think it's OK," Gershoff said. "There's a long history of physically punishing children. Part of it is that people don't want to second-guess their parents -- it's a judgment on them ... People joke about it. They assume you experienced it, too."
But in Sweden, she said, there's now a generation of adults that assumes just the opposite. About half of Swedish children were smacked in the 1970s, before the ban, Save the Children Sweden reported. In the 2000s, the number dropped to "just a few per cent."
The 1979 ban was decades in the making, from the first description of children's human rights in the 1920s, to a ban on smacking in schools in 1958, to the removal of legal language that allowed parents to hit children in 1966. Public attitudes continued to shift in the 1970s after a few high profile cases of discipline gone too far, and in 1977, Swedish Parliament created a committee to examine children's rights. Before the new policy was official, they explained the ban in pamphlets translated into several languages and printed information about it on milk cartons.
The result was Chapter 6, Section 1 of the Swedish Children and Parents Code: "Children are entitled to care, security and a good upbringing. Children are to be treated with respect for their person and individuality and may not be subjected to corporal punishment or any other humiliating treatment." It passed almost unanimously.
The section carries no penalties -- assault cases are still governed by the criminal code, and the number of assault prosecutions hasn't increased, according to a report from the Swedish government and Save the Children Sweden. Instead, adults who hit a child can expect a swift response from Swedish social services, said Joan Durrant, a family social sciences professor at University of Manitoba.
"The police are not going to say, 'This parent should be charged,'" said Durrant, who has studied the effects of Sweden's ban for decades. "The police will say, 'What you did is not OK, I understand why it happened, but you need to know that's against the law, and here are the supports available to you.'"
Those supports might be access to parenting groups, child development information, children's health care or nurses that help childproof homes or offer advice.
It's a typically Swedish response, said Ian Swanson, who is now 31 and living in Minneapolis. His family was at least vaguely aware of the country's ban on physical punishment, but didn't immediately understand what the reaction to a spanking could be.
"It was very much a foreigner's thing. They sort of pitied my parents," Swanson said. "I remember being very afraid that I was going to be taken away. It seemed like a very real possibility. I felt some guilt about it. I was the one misbehaving -- if it weren't for me, they wouldn't be here."
But he also remembers understanding and agreeing with the Swedes' assessment: If parents are hitting, it means they've lost control, and might need to learn about other options.
"[Parents] couldn't understand how someone had the gall -- 'Who in the world can come in and tell me how I'm supposed to raise my child?'" he said. "That's a very American idea. In Sweden, that would not be asked. It's everybody's responsibility."
When Pia Johnson was a teen studying in Sweden, she didn't realize a ban was in place at first. Her peers seemed happier and more independent, she said, but there wasn't an obvious link to children's rights.
Now that she's 45 and a public school teacher in Las Vegas, her view has shifted: Nobody she met in Sweden experienced neglect, and few experienced physical trauma at the hands of their parents. Nobody in Sweden has to wrestle with the questions of what was abuse, what wasn't and what to do next.
"We have a lot of messed-up parents raising kids, teaching their kids to be messed up, as well," said Johnson, who teaches third-graders. "When we call [Child Protective Services], they're like, 'Well, no, that's not exactly it. It's a small bruise.' When we try to advocate, nothing gets done. In Sweden, even if there isn't a bruise, all you have to do is say something."
The Texas video could be a turning point for some, said Durrant, the researcher from Manitoba, but it's hard to imagine a physical punishment ban in the United States at this point.
The United States and Somalia are the only two countries that haven't ratified the United Nations Convention on the Rights of the Child, an international treaty that recognizes the human rights of people younger than 18.
It's a big country, with diverse viewpoints about child rearing. It's expensive and complicated to administer social services. Politically, it's a tough proposition.
"We would have such a divisive argument, and it would take on all these political meanings," said Durrant, an advocate for corporal punishment bans. "Most of us were hit as kids. It's hard to envision what it's like to raise a child without that. The law must go hand in hand with parent support and education."
Aside from the complications of instituting a ban, some researchers doubt it would be effective.
Robert Larzelere, a professor at Oklahoma State University's Department of Human Development and Family Science, said he recommends parents take classes to learn different methods to discipline their kids. Reasoning with kids is great, he said, and "time out" can be a useful tool. But he doesn't want all parents -- or regulations - to rule out a calm, "non-abusive spank" for kids ages 2 to 6.
Spanking young children as a backup to "time out" or reasoning can reduce aggression and noncompliance, he said. But physical punishment shouldn't be rooted in a parent's anger or frustration, he said, and should be phased out as kids get older.
"If we're going to go down this route and impose rules or recommend parents not spank, we need to help them find alternatives that work as well," Larzelere said. "Different things are going to work with different children. We need to be expanding the options parents use to discipline, and use milder discipline tactics more effectively so they don't get to their last resort."
He's also not convinced that bans reduce violence or child abuse, he said, noting that Sweden's statistics for suspected assaults against children have increased, as well as assaults by minors against minors. Other researchers, including Gershoff in Texas and Durrant in Manitoba, said the increase is due to better reporting and lower tolerance for violence.
For as much of a shock as Sweden's ban is to some, Ian Swanson said there were some surprises when his family returned back to the United States, too.
"Kids would say things like 'My dad's going to whup my ass when I come home,' and I sort of didn't really believe that was a possibility," Swanson said. "The first time I actually saw one of my American peers being spanked, I think my jaw hit the floor."
He remembers being spanked exactly once in the United States, after melting G.I. Joes in a frying pan, generating a small-scale fire hazard that momentarily panicking his parents. He probably deserved it, he said.
But once he's a parent, he said, there won't be a question of whether it's deserved: He will not hit his kids.
"I don't care if you hit your kids with a spoon or a belt," he said. "Are you hitting your kids or not? You are? That's the answer -- there's no mystery about that whole thing."