Judges will today rule whether to change a law which allows 17-year-olds to be treated as adults when police arrest them.
The High Court will hear the action, brought by a sixth-form college student and backed by children's rights groups, which is seeking for young people to still be considered children when taken into custody.
It follows the high profile deaths of two 17-year-olds, Joe Lawton and Edward Thornber, who killed themselves after getting into trouble with police.
Joe's parents, Nick and Jane Lawton, say that their son would "still be here today" if he had received their support when he was taken into custody for drink driving.
Mr Lawton told reporters "If we get the change that we are looking for now, it would have meant that we could have been there to support Joe while he was in the police station and explain to him it is not the end - we can get through this, we can help you and make sure that your future is as bright as you expected it ."
The change in law has received backing from the Association of Chief Police Officers but is still rejected by Policing Minister Damian Green, Mr Lawton said.
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.
Ann Thornber, Edward's mother, said that her son had been sent a court summons "in error" rather than a final warning for possessing 50p of cannabis.
"If we had been told and had been informed we would have been able to support Edward going through that crisis and to reassure him that it was a mistake," she said.
"He was 17 and he was being treated as an adult when in theory he wasn't, he was a 17-year-old."
Lacrosse star Edward, from Didsbury, Greater Manchester, was found hanged on September 15, 2011.