Hemophilia is the name of a group of hereditary diseases that affect the body's ability to control blood clotting. Hemophilia is caused by a lack of clotting factors in the blood. Clotting factors are normally released by platelets. Since people with hemophilia cannot produce clots, any cut can put a person at risk of bleeding to death. The risk of internal bleeding is also increased in hemophilia, especially into muscles and joints. This disease affected the royal families of Europe.
Mark had to be very careful not to cut himself. If he did he had trouble getting the bleeding to stop and usually had to go to the hospital. Even a tiny bump could cause him to bruise and bleed under his skin.
Does Mark's blood clot or not?