Based on family history, how likely is it that a couple's children will have a recessive disease? In an in-depth, but easy-to-follow case study, future geneticists learn the story of Greg and Olga, who are hoping to have children, but they are worried about what genetic diseases they may be passing on to their offspring. Divide your pupils into groups and have them work through all six sections of the case study. You may wish to allocate a certain amount of time to each, in order to keep kids on task and to allow for whole-group discussion.