Many traditional books are being replaced by e-books in school.

Nearly 60% of teachers say they utilize e-books because they are less expensive and more accessible than many paper books.

However, there is a major drawback to the use of e-books.

A study suggests teenagers who read traditional books had higher test scores than those who read books on a device.

"Reading from paper is more efficient, meaning that you can understand more in the same amount of time than reading from screens," said Virginia Clinton-Lisell, Ph.D., of the University of North Dakota.

Experts say parents should opt for paper books when they can, but they stress that any type of reading is better than none at all.

"Reading is good. If your kid likes to read from an e-reader, that's awesome. Encourage it as much as possible," Clinton-Lisell said.