Hemophilia is a genetic bleeding disorder that impairs the body's ability to form blood clots. It is caused by defects in the genes responsible for blood clotting factors VIII or IX, and is inherited through the X chromosome. The main symptoms are prolonged bleeding from minor injuries, easy bruising, and bleeding into joints or muscles. Treatment involves replacing the missing clotting factor through infusions of factor concentrates. With effective treatment, people with hemophilia can live normal lifespans, though they remain at risk for joint damage from repeated bleeding. Carriers can have children with hemophilia, with risks varying based on the genetic status of both parents.