Question

in humans, clear sex differentiation occurs not at fertilization but after the second month of gestation. what is the first event of this differentiation?
activation of the sry gene in male embryos and development of testes
formation of estrogens in female embryos
anatomical differentiation of a penis in male embryos
formation of testosterone in male embryos

Explanation:

In human development, the SRY gene (Sex - determining Region Y) is located on the Y chromosome. When the SRY gene is activated in male embryos, it initiates a cascade of events that lead to male sexual differentiation. The first step in male sexual differentiation (after the second month of gestation) is the activation of the SRY gene, which then leads to the development of testes. Testosterone production (formation of testosterone) and anatomical differentiation (like penis formation) are subsequent events that occur as a result of the initial activation of the SRY gene and testes development. Estrogen formation in female embryos is not relevant to male sexual differentiation.

Answer:

activation of the SRY gene in male embryos and development of testes