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: Anatomy
Leydig cells are derived embryologically from 
Select and explain. 
A. Mesoderm of gonadal ridge, B. Endoderm of Genital tubercle, C. Germ cells, D. None of the above
A: Mesoderm of gonadal ridge
Answer: A: Mesoderm of gonadal ridge 
Explanation: Ans. is 'a' i.e., Mesoderm of gonadal ridge Testosterone producing cells, called leyding cells, develop from mesoderm of the gonadal ridge and are located between sex cords.They produce testosterone by week 8.