If a colour blind female marries a man whose mother was also colour blind, what are the chances of her progeny having colour blindness?

A colour blind female has genotype \( X^c X^c \). A man whose mother was colour blind must have genotype \( X^c Y \). Crossing \( X^c X^c \times X^c Y \) yields all children (100%) colour blind (daughters \( X^c X^c \), sons \( X^c Y \)).