Twin pregnancy of the same age and sex rules out ?: (A) Superfetation, (B) Maternal twins, (C) Superfecundation, (D) None of the above
Answer is A. 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