The SRY gene, or Sex-determining Region Y, is a crucial gene located on the Y chromosome. It plays a key role in male sex determination during embryonic development. When the SRY gene is activated, it triggers the formation of testes, which produce male hormones, leading to the development of male physical characteristics. In the absence of the SRY gene, the default pathway is female development. This means that individuals with two X chromosomes typically develop as females. The SRY gene is essential for understanding human sex differentiation and has implications in studies of intersex conditions and gender identity.