In the US, 1 in 1700 Caucasian children will be born with the monogenic hereditary disorder Cystic Fibrosis (CF), a pathology that results in an accumulation of abnormally sticky and thick mucus affecting the lungs and digestive system. Consider a small isolated community in Appalachia where most of the population lives below the poverty level and where adults have a higher rate of CF that the national average since the people tend to marry neighbors. The general practitioner for the county receives a Bill and Melinda Gates Foundation Grant to ascertain how many children in the community inherited cystic fibrosis from their parents. Out of 172 children tested, she finds 38 have CF. Remember that Mendel believed in diagnostic ratios for understanding inheritance outcome although other factors can come into play like assortative mating.