This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Gynaecology & Obstetrics
Twin pregnancy of the same age and sex rules out ? 
Select and explain. 
A. Superfetation, B. Maternal twins, C. Superfecundation, D. None of the above
A: Superfetation
Answer: A: Superfetation 
Explanation: Superfetation It is the simultaneous occurrence of more than one stage of developing offspring in the same animal. In mammals, it manifests as the formation of an embryo from a different estrous cycle while another embryo or fetus is already present in the uterus. Ref : Dutta book of obstetrics 8th Ed