The development of primordial germ cells and gonads are determinants of reproductive health and fertility. Although the gonadal development process is similar for both genders, the gender-determining process and the mechanism of development of female and male gonads have different molecular mechanisms. Spermatogenesis and oogenesis are also included in this process for a healthy gonadal development. Many specific molecular signaling pathways play role in oogenesis and spermatogenesis and it is important to know at which stage these factors are effective, to understand the mechanism of a healthy gonadal development. With this review, we defined the importance of stage specific genes expressing during the events such as oogenesis and spermatogenesis with the prenatal and postnatal gonadal development. It will be important to know about the cellular signals involved in the control of the gonadal development.