Watching too much television as a child may trigger serious health problems such as autism and obesity, and in girls the early onset of puberty, a scientist has claimed.

So great are the dangers, says Aric Sigman, that watching television should be banned for children under three years old and severely restricted as they grow older.

Writing in the journal Biologist, Dr Sigman says that the average six-year-old child in Britain will have already spent a year watching television, and claims that the simple act of staring at a bright television screen, regardless of a programme’s content, can damage a child’s health.

Dr Sigman identified 15 negative effects that, he says, television can have on youngsters, ranging from short-sightedness and diabetes to premature puberty and autism.

“We may ultimately be responsible for the greatest health scandal of our time,” he writes. “Given the evidence, it would be prudent to cordon off the early years of child development as a time when screen media is excluded and then introduced judiciously as the child matures.

“To allow children to continue to watch this much screen media is an abdication of parental responsibility. Truly hands-off parenting.”

Dr Sigman’s report, which is based on his analysis of 35 scientific studies, claims that television viewing affects levels of melatonin, a hormone linked to when puberty occurs in girls. Melatonin levels increase in the evening, at the onset of darkness, but staring into a bright screen during this period hinders its production.

Research has shown that melatonin affects puberty in females more than males. “Animal studies have shown that low melatonin levels have an important role in promoting an early onset of puberty and linked to reproductive function in several sexually mature animals,” Dr Sigman says.

Girls have been reaching puberty earlier since the 1950s, which previous research had blamed on an average increase in female weight, but he claims that lower melatonin levels may be another cause.

Dr Sigman, a member of the Institute of Biology and associate fellow of the British Psychological Society, says that watching television also damages sleep patterns, causes over-eating and increases the risk of type 2 diabetes.

“Television may induce us to eat more [by] causing our brain to monitor external non-food cues — the television screen — as opposed to internal food cues telling us that we have stuffed ourselves and can stop eating.” Low attention spans and poor educational achievement could also be linked to television viewing habits.

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