Reading books is a good habit but a new study has found that popular teen books can be surprisingly sexual, meaning that reading may not always be the wholesome activity that parents expect.

Books aimed at 12 and 13-year-olds were no less sexy than books aimed at readers ages 14 and up. In addition, sex was rarely presented in a healthy light: Contraceptives and practical consequences were almost never mentioned, said study researcher Sarah Coyne, a psychologist at Brigham Young University.