This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Male-female differentiation of fetus occurs at 
Select and explain. 
A. 2-4 weeks, B. 10-12 weeks, C. 16-18 weeks, D. 24-26 weeks
B: 10-12 weeks
Answer: B: 10-12 weeks 
Explanation: Genotype of embryo is established at feilization. But male and female embryos are phenotypically distinguishbletill week 6. Ref: Gray's 39e/p-1289