A man whose father was colour blind marries a woman who had a colour blind mother and a normal father. What percentage of male children of this couple will be colour blind?

1. The Man: His father was colorblind, but the man is normal ($XY$) because he inherited his father's $Y$ chromosome, not the $X$.2. The Woman: Her mother was colorblind ($X^c{X}^c$), so the woman must be a carrier ($X^{c}X$). Her father was normal ($XY$).3. The Cross: $XY\times X^{c}X$.4. Offspring:Daughters: $X^{c}X$ (Carrier), $XX$ (Normal).Sons: $X^{c}Y$ (Colorblind), $XY$ (Normal).Out of the male children, $50\%$ will be colorblind.