Hours spent in front of the TV and playing computer games could increase childhood obesity, a new study warns.
Family life is also at risk from increased use of electronic media devices, with damage being done to emotional well being amongst children ,experts claim.
In the US, paediatric guidelines recommend total screen time should be limited to less than two hours per day of educational, nonviolent programmes.
For every hour of screen time, it is thought the risk to emotional health doubles.
Experts in Britain are now calling for maximum daily screen time limits to be brought in to families here where there are currently no formal guidelines.
Dr Gavin Sandercock, Senior Lecturer in Clinical Physiology, University of Essex, said: "We know that obesity runs in families and this paper shows that the parents of children who get fatter from five to 10 years old are less likely to have rules around TV and screen time.
"In particular, the study reports that mums who don't monitor their young children's screen time may be putting them at risk of becoming overweight or obese.
"Children whose screen time wasn't monitored watched more TV and got fatter more quickly than those living in families with rules around screen time.
"This offers a mechanism to link screen time and fatness and suggests that inactivity comes before obesity in a child's life.
"Children who have rules about screen time are more likely to be active and to go to bed at regular times."
More than 3,600 children took part in a study looking at the use of electronic media between the ages of two and six years, and the wellbeing of children two years later.
Questionnaires were used to measure six indicators of wellbeing, including emotional and peer problems, self-esteem, emotional wellbeing, family functioning and social networks.
Children who watch a lot of TV are likely to be less active and to see more food advertising - both of these factors could contribute to their higher risk of obesity.
