Public figures such as politicians, the royal family and even the clergy, are failing to provide good moral role models for teenagers, sixth-formers attending the lifestyle forum said.
Morality and the speed of scientific progress were their biggest concerns for the future. They said adults expected young people to live by a moral code but failed to do so themselves, leaving teenagers to make their own ill-informed choices.
Some said they wanted morals to be taught in schools, because parents were not tackling the issue at home.
The sixth-formers' concerns emerged during a debate on social issues, chaired by Valerie Singleton, the television presenter. The students talked to representatives from the media, the medical and legal professions, the police and the scientific world.
They were worried that scientists were going too far in the field of genetic engineering and that the public lacked the knowledge to stop abuses. They were particularly concerned about the possiblity of cloning humans.
In a separate debate about the evolution of lifestyle, which examined the place of sport, travel, food and interior design in the lives of young people, sixth-formers complained that PE lessons in schools were short or boring.
Jeremy Cooper, the development officer for the British Association for Sports and Exercise Sciences, told the teenagers that the average of one hour a week devoted to PE and games in secondary schools was not enough to ensure a healthy population.
Chef Brian Turner, star of Ready, Steady, Cook, also expressed concerns that children were no longer being taught about healthy eating or how to cook.