Introduction:
When most people get a cut, the body naturally protects itself. Sticky blood cells called platelets go to where the bleeding is and plug up the hole. This is the first step in the clotting process. When the platelets plug the hole, they release chemicals that attract more sticky platelets and also activate various proteins in the blood known as clotting factors. These proteins mix with the platelets to form fibers, and these fibers make the clot stronger and stop the bleeding.
Hemophilia Definition:
Hemophilia is a genetic disorder—usually inherited—of the mechanism of blood clotting. Depending on the degree of the disorder present in an individual, excess bleeding may occur only after specific, predictable events (such as surgery, dental procedures, or injury), or occur spontaneously, with no known initiating event.
Hemophilia usually is inherited. "Inherited” means that the disorder is passed from parents to children through genes.
The two main types of hemophilia are A and B.
Haemophilia A (clotting factor VIII deficiency) is the most common form of the disorder. Haemophilia B (factor IX deficiency).
If you have hemophilia A, you're missing or have low levels of clotting factor VIII (8). About 9 out of 10 people who have hemophilia have type A. If you have hemophilia B, you're missing or have low levels of clotting factor IX (9).

About World Hemophilia Day:
World Hemophilia Day is observed every year on 17th April to advocate a global effort to ensure appropriate care and treatment for a disease that is the oldest known genetic bleeding disorder caused by a deficiency in the genes.
World Hemophilia Day is targeted to stepping up awareness of hemophilia and other bleeding disorders. The primitive goal of this day is to build mass awareness of bleeding disorders; collect funds and offer improve treatment and care for sufferers of this condition.
World Hemophilia Day was created in 1989 to honor the birthday of Frank Schnabel, World Federation of Hemophilia (WFH)founder. WFH is an international nonprofit organization dedicated to improving the lives of people with hemophilia and other bleeding disorders. Established in 1963, it is a global network of patient organizations that is officially recognized by the World Health Organization.
World Hemophilia Day is an international observance held annually on April 17 by the WFH. It is an awareness day for hemophilia and other bleeding disorders, which also serves to raise funds and attract volunteers for the WFH. It was started in 1989; April 17 was chosen in honor of Frank Schnabel's birthday.
World Hemophilia Day Focuses on Awareness and Outreach.

related links:
http://www.wfh.org/en/