WASHINGTON – President Obama smiled when he said his large ears and funny name once made him a target of school-yard harassment. But he was all seriousness Thursday when he told a White House conference on bullying that torment and intimidation must not be tolerated.

Some 13 million students, about a third of all those attending school, are bullied every year, the White House said. Experts say that puts them at greater risk of falling behind in their studies, abusing drugs or alcohol, or suffering mental or other health problems. Kids who are seen as different because of their race, clothes, disability or sexual orientation are more likely to be bullied.

“If there’s one goal of this conference,” Obama said, “it’s to dispel the myth that bullying is just a harmless rite of passage or an inevitable part of growing up. It’s not.” He spoke to more than 100 parents, students, teachers and others gathered to discuss the problem and share ideas for solutions.

The issue has been getting more attention partly because texting, Facebook, Twitter and other technologies are being used to carry it out and because of media coverage of teenagers who have killed themselves after such taunting.

Families of some of those youngsters joined Obama at the White House, including Tina Meier, of suburban St. Louis. Meier’s 13-year-old daughter, Megan, hanged herself in 2006 after falling victim to an Internet hoax carried out, in part, by an adult neighbor who posed as a boy. The neighbor, a woman, was later convicted of a federal misdemeanor in a landmark cyberbullying trial.

“No family should have to go through what these families have gone through,” Obama said. “No child should feel that alone.”

Meier had a message for parents who want to take away their children’s computers and other electronic devices to spare them from bullying: It won’t work. She urged them instead to get a better understanding of what their kids are doing.

“Technology is out there. We cannot shut it off. Children are not going to allow it to be shut off,” Meier said. “We have to make sure that we have parents who understand what’s going on in their child’s online world, as well as the real world.”