This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
Congenital bilateral absence of vas deferens is genetically related to 
Select and explain. 
A. Noonan syndrome, B. Down syndrome, C. Kartageners syndrome, D. Cystic fibrosis
D: Cystic fibrosis
Answer: D: Cystic fibrosis 
Explanation: Congenital bilateral absence of vas deferens is associated with cystic fibrosis.