More than 50 years after the appearance of the term "gender" in the clinical setting, we have yet to uncover the mechanisms and factors that lead to gender identity formation. Based on human embryology principles, the scientific reasoning with regard to the sexual differentiation of the body is erroneously applied to gender identity formation. The term "embryology of gender" draws attention to the inherent contradictions of trying to apply biological principles to gender development. It is concluded that the clinical management of gender secures the dyad sex:gender by managing the boundaries of what constitutes the acceptable male and female forms. (Contains 1 figure.)