The son in generation II is a carrier for sickle cell disease. He marries a woman who is also a carrier. They have four children who are free of sickle cell disease. How do you explain that outcome? A The woman’s genotype is AS, but her phenotype is normal. B The woman’s genotype must be normal, AA. C As Mendel proved, F1 traits often skip a generation. D They beat the odds. Real life is not like a Punnett Square.