True or False: The presence of the SRY gene on the X chromosome causes an embryo to develop as female.

The assertion that the presence of the SRY gene on the X chromosome causes an embryo to develop as female is false. The SRY (Sex-determining Region Y) gene is located on the Y chromosome, not the X chromosome. It plays a crucial role in male sex determination by triggering the development of male characteristics during embryonic development. When the SRY gene is present and functional, it initiates the formation of testes, which produce male hormones leading to the development of male physical traits.

In the absence of the SRY gene, which occurs when there is either no Y chromosome or a non-functional SRY gene, the embryo will not develop male characteristics and will proceed to develop female characteristics. Thus, the absence of SRY leads to the default pathway of female development, making the understanding of the genetic basis of sex determination clear.

This understanding is essential because it distinguishes the genetic mechanisms that lead to sex differentiation, emphasizing that male development is directly linked to the presence of the SRY gene on the Y chromosome rather than the X chromosome.