Hemophilia Say: hee-muh-FIL-ee-uh When you cut your hand or scrape your knee, it usually will stop bleeding on its own. That's because blood is usually able to form clots that protect you from bleeding too much. But people with hemophilia have blood that doesn't clot the way it should. That means that they bruise and bleed easily and they may bleed a lot or for a long time after an injury. Hemophilia is a genetic condition (meaning it runs in families). Back to Articles Related Articles What's Blood? It swirls through your veins and arteries, but what is it really? Find out about blood in this article for kids. Read More What's a Scab? Just about everyone has had one of these on their knee. Find out how scabs help you heal. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.