Parents, it may sound hard to believe, but letting your kids sleep in could boost their test scores.
Studies show that the teenage body clock runs two to four hours behind adults. Researchers also say that later start times at school could mean an overall better academic performance.
According to British researchers, before puberty, children are the most alert first thing in the morning and don't function as well at night.
They say that the process reverses itself after puberty.
It's called the adolescent "time shift" and continues to the age of 21.
The study, by the University College of London, also says that playing music and games during lessons could potentially boost academic performance. Researchers are also looking at the timing of lessons and whether having classes on Saturday morning could boost performance.