Daniel James was paralysed during a training session
No charges will be brought over the death of a paralysed rugby player in a Swiss assisted suicide clinic.
Mark and Julie James were investigated by UK police after the death of son Daniel, 23, of Worcester, in September.
Director of Public Prosecutions Keir Starmer QC said there was "sufficient evidence" to prosecute the couple.
But he said their "fiercely independent son" had not been influenced by his parents and so charging them would not be in the public interest.
Custodial penalty 'unlikely'
Mr Starmer said: "While there are public interest factors in favour of prosecution, not least of which is the seriousness of this offence, I have determined that these are outweighed by the public interest factors that say that a prosecution is not needed.
"In particular, but not exclusively, I would point to the fact that Daniel, as a fiercely independent young man, was not influenced by his parents to take his own life and the evidence indicates he did so despite their imploring him not to."
He added: "I consider it very unlikely that a court would impose a custodial penalty on any of the potential defendants... in all probability the sentence would be either an absolute discharge or, possibly, a small fine."
Mr Starmer said that Mark James had told him in interview that "even up to the last second... I hoped he'd change his mind... and my wife... I know she felt exactly the same."
The Crown Prosecution Service said no charges would be brought against a family friend, also under investigation by West Mercia police, who helped with the travel arrangements to Switzerland.
Mr James, a third year construction engineering student at Loughborough University, had played for Nuneaton Rugby Club, the England Universities rugby team and England Students team.
He was paralysed from the chest down, with no independent hand or finger movement, as a result of an injury sustained in a scrum while training at Nuneaton Rugby Club on 12 March, 2007.
Eight months later he was informed he would never make a significant recovery.
After the accident he tried to kill himself three times.
His parents were at his bedside when he died at the Dignitas clinic in Switzerland on 12 September.
Writing to Dignitas, Mr James said that "not a day has gone by without hoping it will be my last".
Psychiatrists said Mr James had arrived at his decision using clear, coherent and logical thought processes.
A consultant psychiatrist said after an assessment in March that Mr James was "fully aware of the reality and potential finality of his decision".
The campaign group Dignity in Dying welcomed the CPS's decision and said the law should be clarified.
The organisation's head Sarah Wootton said a lack of a safeguarded choice forced people into making "desperate and often dangerous decisions".
She said: "People are travelling abroad to die, there are 'mercy killings', botched suicides and some doctors already assist their patients to die at great potential cost to their livelihood and freedom."