The more teenagers use gadgets before bedtime, the worse their sleep patterns get, a study shows.
But researchers say parents need only cleanse their kids' bedrooms of technology in the most extreme cases.
Teens who used computers, mobiles or TV right before bedtime generally fell asleep and woke later than those who didn't, according to an online survey of 11,400 Australians aged 11-17.
They were also more likely to wake up later on weekends, indicating their body's need to catch up on missed sleep.
But only those who reported using technology in bed "nearly every night" had more serious sleep issues.
Those who almost always took their computers to bed were 2.5 times more likely to have shorter sleep than those who didn't, according to the research published in the journal PLOS ONE.
The results don't necessarily mean modern technology is causing poor sleep across the board, said co-author Dr Nat Marshall from Sydney's Woolcock Institute.
People might, for example, be using technology to fill the time when they can't sleep anyway, he said.
"Our parents might have listed to AM radio and our grandparents were burning down the barn by reading by candlelight."
He said a small minority had genuine issues with using technology too much.
"If you've got a kid who's genuinely not getting enough sleep because they can't stop themselves from using technology, you maybe should take it out of the bedroom," Dr Marshall said.
"But having a TV and a radio and cellphone in your room at night isn't going to automatically ruin your sleep."
Studies suggest about 25-40 per cent of teenagers will suffer from poor sleep at some point.