Compare and contrast amniocentesis and chorionic villus sampling as to the time at which they can be performed and the techniques used to obtain information on the fetus’s genetic status. A...

Compare and contrast amniocentesis and chorionic villus sampling as to the time at which they can be performed and the techniques used to obtain information on the fetus’s genetic status.

A colour-blind man marries a woman with normal vision. The woman’s father was also colour-blind.

(a) What is the chance that their first child will be a colour-blind son? A colour-blind daughter?

(b) If they have four children, what is the chance that two will be colour-blind sons? (Be careful on this one.)