Kristin and Mike Song are still in disbelief that their 15-year-old son, Ethan, is gone. He accidentally shot himself last year when he was at a friend's house, playing with guns.

"They were stored in a cardboard box, along with the ammo. There was a gun lock in there but the keys were in there," Mike Song said.

The Songs had no idea the home had firearms and they said careless gun storage cost their son his life.

"Ethan pulled the trigger and he was shot in the head, so he really had no chance of survival," Kristin Song said.

A recent study by Harvard researchers estimated up to 32% of youth firearm deaths by unintentional injury and suicide could be prevented if guns were properly locked and stored and ammunition is kept separately.

Ethan Song Family handout

Only three states and Washington, D.C. make unsafe storage, regardless of whether a child ever touches the gun, a crime. There is no federal law for safe gun storage. But now, the Song family is fighting for one in their son's name.

Ethan's Law was introduced to Congress on Tuesday. It states unsafe storage of a firearm resulting in injury or death of a minor is a crime and punishable by up to five years in prison.

"I respect people's rights to own a gun. And I know that my son's dead now," Mike Song said. "So, I think there are reasonable limitations that we can talk about together and start a dialogue that could save thousands of lives."

In a statement to CBS News, the National Rifle Association said "there is no scientific evidence that government mandated, one-size-fits-all storage schemes reduce juvenile, accidental firearm deaths or suicides." But they said it could make it harder for law abiding citizens to protect themselves.