CHICAGO - President Obama punctuated a week spent promoting his economic agenda with an emotional appeal on the impact of guns.

Speaking at a Hyde Park high school, the last stop on his post-State of the Union tour, Obama reflected on the root causes of an epidemic of gun violence that has plagued cities across the country. In his hometown Chicago, more than 500 were shot and killed last year, making it the epicenter of a national problem.

Obama said absent fathers, particularly in the African-American community, and broken marriages are one of the contributing factors in cases of youth poverty, violence and crime. He said one of the solutions is strengthening parental role models.

"There's no more important ingredient for success, nothing that would be more important for us reducing violence than strong, stable families, which means we should do more to promote marriage and encourage fatherhood," Obama said.

"You know, I - don't get me wrong. As the son of a single mom who gave everything she had to raise me, with the help of my grandparents, you know, I turned out O.K.," he continued. "But at the same time, I wish I had had a father who was around and involved."

Before taking the stage, Obama spent over an hour meeting privately with a group of male students from Hyde Park Academy, many of whom come from at-risk backgrounds, some without fathers involved in their lives, and have a personal connection to gun violence.

"A lot of them have had some issues. That's part of the reason why you guys are in the program," Obama said later. "But what I explained to them was, I had issues too when I was their age. I just had an environment that was a little more forgiving. So when I screwed up, the consequences weren't as high as when kids on the South Side screw up. So I had more of a safety net.

"But you guys are no different than me. And we had that conversation about, what does it take to change? And the same thing that it takes for us individually to change, I said to them - well, that's what it takes for communities to change. That's what it takes for countries to change," he said. At the top of his remarks, Obama invoked the memory of local student Hadiya Pendleton as a symbol of the tragic cost of urban killing. The South Side teenager was gunned down days after performing at the inauguration in a park three miles from here.

"Too many of our children are being taken away from us," Obama said in a gymnasium here as Pendleton's parents looked on from the front row.

"Last year there were 443 murders with a firearm on the streets of this city, and 65 of those victims were 18 and under," he said. "So that's the equivalent of a Newtown every four months. And that's precisely why the overwhelming majority of Americans are asking for some common-sense proposals to make it harder for criminals to get their hands on a gun."

Earlier today, Obama presented the Presidential Citizens Medal to families of six adult victims of December's shooting massacre at Sandy Hook Elementary - a day Obama has called the worst of his presidency. But Pendleton's story has also touched the Obamas in many of the same ways, her death occurring blocks from the first family's private home in Kenwood.

Last weekend, First Lady Michelle Obama attended Pendleton's funeral in Chicago; Hadiya's parents were invited guests at the State of the Union on Tuesday night.

While Obama today called for an "up or down vote" on his gun control plan, he said cities like Chicago demonstrate that the roots of the problem run deeper and require solutions that no single law can provide.

"When a child opens fire on another child, there is a hole in that child's heart that government can't fill," he said. "Only community and parents and teachers and clergy can fill that hole."