A staggering four out of five parents worry that their children will become addicted to Facebook, according to a study.
Eighty percent believe social networking sites such as Facebook and Twitter have the ability to take over their children's lives.
One in three parents, meanwhile, believes the Internet has the power to 'rewire' brains without a person's knowledge and thinks their children are in danger from the web.
The extraordinary findings come from a poll of 1,000 parents carried out by the Nominet Trust, an organisation that promoted internet projects that address social disadvantage.
However, Nominet said their findings fly in the face of neurological evidence.
The Trust worked with neuroscience and education expert Dr Paul Howard Jones, who analysed research on the internet and society.
The report - The Impact of Digital Technologies On Human Wellbeing - concluded that there is no neurological evidence to suggest that the internet is more effective at 'rewiring' our brains than other environmental influences.
It also found that the internet is a valuable learning resource and all forms of learning cause changes within the brain.
There have been reports that use of the internet with its vast resources of information is changing the way people think and affecting their ability to concentrate.
But Nominet said that 'scaremongering and misinformation' about internet use can potentially deny its benefits to people, in particular parents who are worried about the effect on their children's development.
The report also found that social networking sites, in themselves, are not a special source of risk to children, and are generally beneficial as they support existing friendships.
In addition, playing action video games can improve some visual processing and motor response skills, while computer-based activity provides mental stimulation, and can help slow rates of cognitive decline.