If differing Rh factors between a mother and fetus lead to a blood incompatibility, which of the following medical conditions could arise in the newborn baby? 

• A. Anemia. 
• B. Erythroblastosis fetalis (newborn hemolytic disease). 
• C. Leukemia. 
• D. Hemophilia. 

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the Rh factor and its role in blood compatibility. The Rh factor is a protein found on red blood cells; individuals are either Rh-positive (have the protein) or Rh-negative (do not have the protein).
2. Step 2: Recognize that if an Rh-negative mother carries an Rh-positive fetus, the mother's immune system may recognize the fetus's Rh-positive red blood cells as foreign and produce antibodies against them.
3. Step 3: These maternal antibodies can cross the placenta and attack the fetal red blood cells, leading to their destruction, a process known as hemolysis.
4. Step 4: The destruction of fetal red blood cells causes anemia in the fetus and can lead to a condition called erythroblastosis fetalis, also known as hemolytic disease of the newborn.
5. Step 5: Differentiate erythroblastosis fetalis from other conditions listed, such as leukemia (a cancer of blood cells), hemophilia (a bleeding disorder), and anemia (a general term for low red blood cells), noting that erythroblastosis fetalis specifically results from Rh incompatibility.