Which one of the following techniques is employed in human genetic counselling?

Colour blindness is a disease usually affecting men,but the factor for it is transmitted to the children always by the woman. This is because the particular factor is located on

Recessive characters are expressed:

$A$ color-blind man marries a woman with normal vision,whose family has no history of color blindness. What is the probability that their daughter's children (grandsons and granddaughters) will be color-blind?

Which of the following is controlled by a recessive gene in humans?

If a colour blind lady marries a normal man,their children will be: