Question

A normal woman, whose father was colour blind is married to a normal man. The sons would be

• A. All colour blind
• B. 75% colour blind
• C. 50% colour blind
• D. All normal

Answer 1

Answer: (C)

50% colour blind

Normal woman whose father was colour blind will be a genetic carrier of colour blindness (X${}^c$X). If that woman marries a normal man, XY, the offspring formed will be :
X${}^c$X x XY
XX (normal female), XY (normal male), X${}^c$X(Carrier female) and X${}^c$Y (colour blind male).