This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Congenital malformations, Subject name: Gynaecology & Obstetrics
All of the following take pa in male genital tract development except; 
Select and explain. 
A. SRY, B. SOX-9, C. FGF-9, D. WNT4
D: WNT4
Answer: D: WNT4 
Explanation: SRY is a transcription factor and master gene for testes development.It appears to act in conjuction with autosomal gene SOX-9,transcriptional regulator that can induce testis differentiation.SOX-9 binds to promotor region of gene for AMH substance and regulates its expression.They both induce secretion of FGF-9 that act as a chemotactic factor that make tubules from mesonephric duct to penetrate gonadal ridge.SRY directly or indirectly upregulates steroidogenesis factorwhich differentiates leydig and seoli cells. LANGMAN&;S MEDICAL EMBRYOLOGY,12 TH EDITION ,Pg no:246