Slide show: Birthmarks

Contrary to their name, birthmarks aren't always present at birth. Some, such as hemangiomas, develop weeks later. Most birthmarks are permanent, but a few types fade as a child grows.

Birthmarks are common and usually harmless. But some may require treatment for cosmetic reasons or because of rapid growth. Still others may be a sign of an underlying disease. Take this visual tour of cafe au lait spot (pictured), port-wine stain and other common birthmarks to find out when your child might need to see a doctor.