Research reveals that more than half of parents with teens in social networking Web sites such as Facebook and Twitter believe that their children are becoming dumber.

In spite of the figures, less than half of the parents in the survey believe that the sites have an effect on their children's health and wellbeing. The research, which is commissioned by Telstra, the telecommunications company, finds that 65 per cent of parents with children using social media say that the Web sites distract their teens from homework, which thereby contributes to a lack of enthusiasm for learning.

A quarter of parents who were interviewed say that their teens spend more than seven hours a week logged on to such Web sites. Less than 40 per cent, on the other hand, fear that the behavior affects their children's wellbeing. In an interview with the Sunday Herald Sun, Dr Martyn Wild, an expert on cyber safety, says that parents often do not know what their children do online.

"The answer is not turning off internet access, rather it's about implementing simple behavioral changes in your children and setting realistic expectations about their use of the internet," Dr Wild said.

In addition to the research, Telstra launched a Web site on cyber safety to give parents advice on keeping children safe online. The Web site, designed to provide users of all ages with information, is located at www.telstra.com.au/cyber-safety.