Practice question

Absence of functional SRY in mammalian embryos prevents activation of testis pathway. Without Sry-mediated upregulation, Sox9 remains low, Fgf9 amplification loop fails, pre-Sertoli cells do not form and Amh and Dhh never expressed. Consequently antagonistic ovarian pathway driven by Wnt4, Rspo1, β-catenin and Foxl2 prevails, directing supporting lineage toward granulosa cells, allowing germ cells to enter meiosis and forming ovary with cortex-medulla organization. XY individuals with SRY deletions or loss-of-function mutations therefore develop as phenotypic females, while normal XX gonads naturally follow ovarian trajectory.