Multiple choice

In a couple, if the father of the child is Rh positive and the mother is Rh negative, what are the chances that there will be erythroblastosis fetalis problem? They already had a son and the couple has taken no medical treatment to avoid this condition.

  1. 100%

  2. At least 50%

  3. Less than 50%

  4. 0%

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If the father is homozygous dominant (DD), the chances of the fetus being Rh positive and an incompatibility problem occurring will be 100%. If the father is heterozygous (Dd), the chances are 50%. There will be no problem if the fetus is Rh negative.