Question

A woman has normal vision, but her father is colourblind. If she marries a colourblind man, then what is the probability of her son being colourblind?

Options

• 25%

• 50%

• 75%

• 100%

Answer 1

50%

Explanation:

The woman has normal vision but her father is colourblind, so she is a carrier (XⁿX^c). The colourblind man is X^cY. Sons get Y from father and X from mother. The mother can pass Xⁿ (normal) or X^c (colourblind) with equal chance, so 50% of sons will be colourblind.