Question

For a heredity point of view, which marriage is not suitable?
A) Man Rh(-) and Woman Rh (+)
B) Both Rh (+)
C) Both Rh (-)
D) Man Rh (+) and Woman Rh (-)

Answer 1

Hint: For the very first time this concept was proposed by Karl Landsteiner and A.S. Weiner in the year 1940.

Complete answer:
On a hereditary point of view, marriage between an Rh-positive man and an Rh-negative woman is not suitable. This results in the fetus Rh antigens acting as foreign invaders in the mother’s body. This starts the defense mechanism that will harm the fetus during the second pregnancy. This is known as erythroblastosis foetalis.

Additional Information:
A system for classifying blood groups according to the presence or absence of the Rh antigen is known as the Rh blood group system. Rh factor is present on the cell membranes of the red blood cells (erythrocytes). Rh is derived by using the blood of rhesus monkeys in the basic test for determining the presence of the Rh antigen in human blood. Since then several distinct Rh antigens have been identified. The most severe immune reaction is caused by RhD and it is the primary determinant of the Rh trait.

So, the correct answer is Man RN (+) and Woman Rh (-).

Note:
During pregnancy, the Rh-positive offspring of Rh-incompatible parents, (when the mother is Rh-negative and the father is Rh-positive). The first child is in no danger unless the mother has acquired anti-Rh antibodies. Its treatment entails one or more exchange transfusions. It can be avoided by vaccinating the mother with Rh immunoglobulin after the delivery of her firstborn. The vaccine destroys any fetal blood cells before the mother’s immune system can develop antibodies.