One in five young people think their parents have taken drugs, according to a survey published on Sunday.
One in ten of those think their parents still take them, while only 1% of parents questioned think their own children take drugs.
In the poll, commissioned by specialist drug and alcohol charity Addaction, over half of young people said their parents "understand about drugs".
The charity suggested that the present generation parents were more familiar with drugs than in the past because they grew up in the "rave generation" of the 1980s.
On Monday(October 6) Addaction is launching a £10 million appeal to respond to the scale of drug and alcohol abuse among young people in the UK.
Of the young people surveyed however, 90% described themselves as being "against drugs" and nine in ten also feel "little or no pressure" to take drugs when with friends. Only one in ten said celebrities taking drugs seem "cool" - yet two thirds of parents are concerned about the impact of this on their children.
Two thirds of adults think illegal drug use among young people is increasing and 83% said parents "don't take enough responsibility" for their children's behaviour. But only 8% of young people said they would be likely to tell their parents if they were using drugs, with two in three preferring to confide in friends.
Commenting on the findings, chief executive of Addaction Deborah Cameron said: "The rave generation of the 80s have grown up and become parents.
"This should give us the basis for more realistic discussions between parents and children about drugs, but our concern is that the demonisation of these issues often means the debate takes place in a moral panic."
She said as many as one in six families are now affected by a family member's problem drug use. "We want to encourage a much more open dialogue within families about drugs and alcohol," she added.
