The inevitable falls and bumps which occur in toddlers may cause skin bruises and bleeding from the lips and tongue. Injections given into the muscle in the usual manner can produce a large, deep bruise which may be dangerous. The body is formed by millions of cells. Each cell has a central controlling part called the nucleus which contains chromosomes, paired thread-like structures, which determine the development of characteristics of each individual person. The most obvious characteristic determined by the chromosomes is whether a person is male or female.
Every chromosome is composed of many units called genes which determine the body s functions.
X chromosome produces a sufficient amount of factor. In each pregnancy involving a female carrying the hemophilia gene there is a 1 in 2 chance that the hemophilia gene will be passed on, and when this happens a male child will have hemophilia, and a female will be a carrier of the hemophilia gene. In other words, for each pregnancy there is a 1 in 4 chance that the child will be male with hemophilia, as shown in Figure 1. None of his sons will have hemophilia, they will have normal amounts of clotting factor, and they will not pass the disorder on to their children. When the father has hemophilia All the sons will be unaffected.