This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Types of Genetic Disorders, Subject name: Pediatrics
True statement about inheritance of an X-linked recessive trait is: 
Select and explain. 
A. 50% of boys of carrier mother are affected, B. 50% of girls of diseased father are carrier, C. Father transmits disease to the son, D. Mother transmits the disease to the daughter
A: 50% of boys of carrier mother are affected
Answer: A: 50% of boys of carrier mother are affected 
Explanation: For a X-linked recessive disease: If mother is a carrier: If father is diseased: 50% of boys of carrier mothers are affected All daughters are carriers Mothers transmit defective gene to 50% of the sons (diseased) as well as daughters (carriers) Fathers transmit defective gene to daughters