A generation ago, fewer than 5 percent of girls started puberty before the age of 8; today, that percentage has more than doubled. Early puberty is not just a matter of physical transformation--it's also deeply psychological, with a myriad of effects that can put a girl at higher risk for behavioral problems and long-term health challenges.

In this reassuring and empowering guide, Louise Greenspan, MD, and Julianna Deardorff, PhD--two leading experts on the root causes and potential consequences of early puberty in girls--deliver vital advice on how to prevent and manage early...