This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intersex, Subject name: Gynaecology & Obstetrics
A 16-year-old girl with primary amenorrhea comes to OPD with bilateral inguinal swelling. She has normal breast development with no pubic hair. USG shows absent uterus. The diagnosis is: 
Select and explain. 
A. Androgen insensitivity syndrome, B. Turner syndrome, C. Mullerian agenesis, D. Klinefelters Syndrome
A: Androgen insensitivity syndrome
Answer: A: Androgen insensitivity syndrome 
Explanation: Testicular feminization syndrome (androgen insensitivity syndrome): XY karyotype with a female phenotype androgens are present but do not act at a peripheral level due to a receptor defect. the embryological development, which is dependent on androgens in a male fetus, does not happen and hence by default a female form is made. breast development is seen due to peripheral conversion of androgens to estrogens The inguinal swellings described in the question are actually the testes