Men have XY (or YX) chromosomes and women have XX chromosomes. X-linked recessive genetic diseases occur when there is a defective X-chromosome that occurs without a paired X chromosome that is not defective. Represent a defective X chromosome with lowercase x, so a child with the xY or Yx pair of chromosomes will have the disease and a child with XX or XY or YX or xX or Xx will not have the disease. Each parent contributes one of the chromosomes to the child. A). If a father has the defective X chromosome and the mother has good XX chromosomes, what is the probability that a sin will inherit the disease