A couple decides to have a child and consult with genetic counselor because each of them is a carrier of different genetic disorder. The woman is a carrier for cystic fibrosis (CF) and the man is a carrier of mutation causing Gouache disease . Cystic fibrosis is caused by mutation in CFTR gene and Gaucher disease by mutation in GBA gene, so each parent have one copy of mutant allele and one normal. (Both diseases are autosomal recessive)

A. Draw a Punnett square for the child

B. What is the probability that their child will be a carrier for both of the diseases?

C. If the child is a carrier for both diseases, and in the future that child marries a carrier both diseases, what is the probability for them to have a healthy child.

D. Use a mathematical equation to support your answer from the calculation using Punnett square (c).