Genetic Counselor Couple Example (For reference)

- Suppose a couple both have a brother who died from the same recessively inherited disease​ - A genetic counselor can help determine the risk that this couple will have a child with the disease​ - It is important to remember that each child represents an independent event in the sense that its genotype is unaffected by the genotypes of older siblings​ - If both members of the couple had a sibling with the recessively inherited illness, both of their parents were carriers​ - Thus each has a ⅔ chance of being a carrier themselves​ - If both are carriers, there is a ¼ chance of each child having the recessive illness​ - The overall probability of them having a child with the illness is ⅔ × ⅔ × ¼ = 1/9​