1.Why are X-linked recessive disorders never passed from a father to a son? 2. The pedigree for Queen Victoria of England, a carrier of hemophilia A, shows the transmission to some of her descendants,...

1.Why are X-linked recessive disorders never passed from a father to a son?

2. The pedigree for Queen Victoria of England, a carrier of hemophilia A, shows the transmission to some of her descendants, including members of many royal families in Europe, such as Russia and Spain, but not Germany. Hemophilia A does not affect anyone in the present British royal family. Can you explain why hemophilia A has disappeared from one family and appeared in others?