The families of two 17-year-old boys who killed themselves after being arrested are delivering a petition to Downing Street, calling for a change in the law.
Nick and Jane Lawton's son Joe committed suicide two days after he was arrested for drink-driving last August.
Adrian and Ann Thornber's son Edward also took his own life after being summoned to court for possessing 50p worth of cannabis.
In both cases the parents were not informed of the arrests because their sons were treated as adults in custody.
The families have now joined forces to call for the government to address the "anomaly" that 17-year-olds are treated as adults when arrested but as children if they are charged.
Mr Lawton told BBC Breakfast that he hoped the "groundswell" of public support would encourage ministers to act after more than 50,000 people signed the petition.
"Joe was our only child so we're not doing this for ourselves," he said.
"We don't want other families to go through what we went through. It's dreadful."
He said Joe felt "ashamed" and "embarrassed" about his arrest but he was denied the chance to offer support to his son.
"He couldn't find the words to tell us and he needed the support of his family at that very difficult time," Mr Lawton added.
Joe, from Stockport, Greater Manchester, was arrested when police stopped him after he decided to drive his new car
home from a party.
He was kept overnight at Cheadle Heath police station in Greater Manchester without his parents' knowledge.
Two days later he took his own life, using the shotgun from the family farm.
The police charge sheet was at his feet when his father found him.
Teenage lacrosse star Edward Thornber, from Didsbury, Greater Manchester, was found hanged on September 15 2011.
Two days earlier, the former head boy had received an order to appear in court after being caught smoking cannabis in Cornwall.
Both families say that if the law is changed it will bring the UK into line with the United Nations convention on the rights of the child.
It states that every person under 18 must be treated as a child if they are considered such in the eyes of the law of that country.
A judicial review into the issue is ongoing.
Shauneen Lambe, executive director of support charity Just For Kids, said: "The Home Secretary can easily make this change.
"She has said the decision is finely balanced.
"I would hope that calls from 50,000 people across the UK and the heartbreaking stories of these two families is enough to tip the balance."