"Sry, the mammalian Y-chromosomal testis-determining gene, is a master regulator of male sex determination. It acts to switch the undifferentiated genital ridge towards testis development, triggering the adoption of a male fate. Sry initiates a cascade of gene networks through the direct regulation of Sox9 expression and promotes supporting cell differentiation, Leydig cell specification, vasculature formation and testis cord development. "

"The body of this individual will react to testosterone, because the fact that someone has a high level of testosterone, but for example a genetic mutation that makes the cells not react to this testosterone, will make this development rather tend towards female. "