The European Court of Human Rights will allow French doctors to take a paralysed man off life support despite objections from his parents.
The court upheld a decision by France's top administrative court, who ruled that doctors could end the intravenous food and water keeping Vincent Lambert alive.
The 38-year-old was a victim of a car crash in 2008, and has been in a vegetative state ever since.
Following the crash, Mr Lambert was declared a quadriplegic.
The high-profile case has pitched Mr Lambert's parents and two of their children against five other children and Lambert's wife Rachel, who won French clearance last June for doctors to effectively end her spouse's life after years in a coma.
The ruling comes during a intense debate in France over euthanasia and the right to die.
Doctors treating the 38-year-old in the northeastern city of Reims, as well as his wife, nephew and six of his eight siblings succeed in convincing France's top administrative court, the State Council, in 2014 to allow them to turn off his life support system.
However, his deeply religious Catholic parents, and one brother and sister, opposed the decision, and took the case to the European Court of Human Rights.
In their court application to stop the plan, they argued that Mr Lambert was suffering from a “handicap”, not an “incurable brain disease”.
Turning down an appeal, the court, based in Strasbourg in eastern France, said the earlier French court decision was in line with the human rights convention
The ruling by the European Court of Human Rights cannot be appealed.