Two people with normal vision have two sons, one color blind and one with normal vision. If this couple then has six daughters, what percentage of the daughters should have normal color vision?

Question

Quizplus · Accepted Answer

The father is color blind and the mother has normal vision. The father can only pass on the color blind gene to his sons, so one son is color blind and the other has normal vision. The mother can pass on either the normal gene or the color blind gene to her daughters, so each daughter has a 50% chance of having normal color vision. Therefore, 50% of the daughters should have normal color vision.

Two People with Normal Vision Have Two Sons, One Color