A birthmark is a special spot on your skin that you’re born with. Birthmarks can be different colors and shapes, and can be found anywhere on your body. But how did they get there in the first place? We asked dermatologist Dr. Julie Schultz to help us find the answer.

Got a question that’s made a mark on your brain? Send it to us at BrainsOn.org/contact, and we’ll help get the skinny on that topic.