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 16 yr old female presents with Primary Amenorrhea. Examination shows a Sho Blind Vagina, with absent Uterus. The Next Investigation of choice is : 
Select and explain. 
A. Karyotyping, B. IVP, C. Gonadotrophin levels, D. Serum Prolactin
A: Karyotyping
Answer: A: Karyotyping 
Explanation: Karyotyping A female phenotype presenting with absent uterus and sho blind vagina : Friend what are the D/D's which come to your mind. I can think of only 2 : Mullerian dysgenesis and Testicular feminizing syndrome (or male pseudo hermaphroditism). So, the best way to differentiate between the two is to do karyotyping or chromatin/barr body test. Which comes positive (barr body present) in 46XX and negative (barr body absent) in case of 46XY Genotype.