Question

Which of the following is a biologically incompatible marriage?

• A. Rh$+$ man and Rh$-$ woman
• B. Rh$+$ man and Rh$+$ woman
• C. Rh$-$ man and Rh$+$ woman
• D. Rh$-$ man and Rh$-$ woman

Answer 1

The correct option is A Rh$+$ man and Rh$-$ woman

The Rh-positive character is dominant. If an Rh-positive man marries an Rh-negative woman, then the first foetus (and foetuses thereafter) will be Rh-positive. In this case, the Rh-positive antigen from the foetus will enter into blood stream of the mother and there will be formation of anti-Rh antibodies in mother’s body. During her second pregnancy, these antibodies will attach the red blood cells of the Rh-positive foetus and coagulate the blood, resulting in severe complications.

If the mother is Rh-positive and father is Rh-negative, then foetus will be Rh-positive and there will be no complication.

Hence, the correct answer is ‘Rh+ man and Rh- woman’