Hemophilia is a condition in which blood does not clot properly. What is the main effect of this condition?

Your blood does not clot properly, because it lacks sufficient blood-clotting proteins.

decreased ability to heal blood vessel wounds

A blood clot stops the flow of blood from a damaged blood vessel. The vessels then undergo repair, and the wound heals. In hemophilia, the body loses the ability to form clots, which decreases the body's ability to heal wounds.