Do you carry an X-linked genetic disease such as hemophilia or Duchenne Muscular Dystrophy?

X-linked diseases are carried by women, but generally appear only in males. Women have two X chromosomes and can carry a mutation on one X chromosome that can be passed on to their children. Half of their sons will inherit the mutation and be affected with the disease. Half of their daughters will inherit the mutation and thus be carriers like their mother. Carrier females have no clinical symptoms for most, but not all, X-linked genetic diseases. Since only boys are affected for most X-linked genetic diseases, couples can elect PGD for gender determination to have a female, thus reducing the chance of having a child with an X-linked genetic condition.

I want learn more about PGD for gender selection.