Sexuality and endocrine glands

Abstract

In the fifties, Jost, the French endocrinologist, on the basis of his research concluded that the theory of the Bi-sexual phase of the initial embryonic existence is incorrect. He discovered that the early embryo is not undifferentiated, it is differentiated. It is a female. In the beginning we were all created females. Genetic sex is established at fertilization, but the influence of the sex genes is not brought to bear until the fifth to the sixth week of fetal life. The process is as follows: 1. If the genetic sex is female, the germ cells migrate to the gonadal cortex. There, the ovaries are formed and fetal estrogen is eventually produced. However, if for some reason the ovaries would not develop, the fetus will still be a female although with abnormalities. Consequently, the development of the female is autonomous, nothing has to be added. 2. If the genetic sex is male, the primordial germ cells migrate from the endoderm of the yolk sac, to the gonadal medulla. There, the germ cells stimulate the production of a testicular inductor substance which subsequently stimulates the elaboration of the fetal androgen. Androgen suppresses the growth of the oviducts and gonadal cortex, and induces the growth of the internal and external male genital tract. 3. Genetic sex is not the only factor assuring the physical development of a sexually normal individual. There must be an optimal amount of hormones. The hormones must be properly metabolized. In the genetic male, there must not develop an immunity toward androgens. Equally important is the normal amount and normal configuration of the sex chromosomes. 4. To produce a male, androgenic steroids must start to function at the critical period of development. They will have a decisive influence on the