KidsHealth is a project of The Nemours Foundation, a nonprofit organization devoted to children's health. Copyright 1995- The Nemours Foundation. All rights reserved. KidsHealth and KidsHealth.org are Trademarks of The Nemours Foundation. TeensHealth and TeensHealth.org are Service Marks of The Nemours Foundation. Displayed under license. All other content and trademarks are the property of their respective owners.
Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.
© 1995-2017 KidsHealth ® All rights reserved. Images provided by iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com