ABSTRACT
This chapter explores the difference between genetic and gonadal sex. It examines the hormonal determinants of sexual development and presents some examples of that role. The chapter provides the examples of human differentiation pathophysiology. Genetic sex is determined by the sex chromosomes. Genetic sex is determined when male and female gametes fuse at conception. Gonadal sex refers to the presence of an ovary or testis, whose presence and proper function are required for sexual female and male reproductive competence respectively. Secondary sexual characteristics determine the phenotype, for example, female breast and external genitalia development, and male typical muscular configuration, hair distribution and external genitalia development, as well as development of male accessory sex organs. In the absence of a testis, the female phenotype develops, together with the internal secondary sexual organs, that is, the fallopian tube, uterus and part of the vagina, which are formed from the Mullerian ducts.
