The sex glands are not only the site where sex cells (spermatozoa and ova) are formed, but also have a function of internal secretion, discharging sex hormones into the blood. These hormones fall into two groups: the male sex hormones or androgens, and female sex hormones or oestrogens (oestrus, the period of ovarian hormonal activity or the period of heat). Both types are produced in the male and female gonads, but in different amounts, which can be determined from the urine, in which they are eliminated from the body. The physiological role of the sex hormones consists in ensuring the sexual activity of the organism. They are necessary for sexual maturation, i.e. for the development of the organism and its genital apparatus that makes the sexual act and reproduction possible. They are responsible for the development of secondary sex characters, i.e. of peculiarities of the sexually-mature body that are not directly associated with sexual activity but are specific features distinguishing the male and female organisms. From psychological point of view is important the tertiary sexual characteristic. At the human species appears other sexual charac-teristics: fourth, fifth and sixth. We note that this part is functioning also under normal circumstances, only the brain activity obscures (masks) the everyday activity of the hypothetical secondary brain