In humans, clear gender differentiation occurs not at fertilization, but after the second month of gestation. what is the first event of this differentiation?

The first event of this differentiation is the activation of SRY in females and feminization of the gonads. Initially, the cells of the gonad are bipotential. This means they have the potential to be either male or female. Activation of male-specific transcription factors y TDF allows the gonad to differentiate and proliferate into a male.