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
A women has had 2 previous anencephalic babies, risk of having a third one is: 
Select and explain. 
A. 0%, B. 10%, C. 25%, D. 50%
B: 10%
Answer: B: 10% 
Explanation: The risk of recurrence of anencephaly:
If one child is affected 5%
If two children are affected 13%