When you put yourself to bed each night, do you still see a sliver of light under your teenager’s bedroom door?

If your teen is like many others, chances are he or she is staying up later than is recommended.

A new national study, reported in an article by Knight Ridder Newspapers, blames the many electronic gadgets that the average teen has in his or her bedroom for the trend.

Computers, cell phones, televisions and video games all keep those who should be asleep wide awake, said Jodi A. Mindell, associate director of the Sleep Center at Children's Hospital of Philadelphia and coauthor of the study. As a result, more than a quarter of high school students fall asleep in school at least once a week.

Mary Carskadon, director of the E.P. Bradley Hospital Sleep center at Brown University and the other study author, said that an optimal night's sleep for teens is nine hours. But researchers found that almost half slept fewer than eight hours on school nights.

Teachers, are teens falling asleep in your classes? Teens, why do you stay up late when you should be getting your rest? And parents, how do we fix this problem? Take away the toys?