ABSTRACT
Androgens and oestrogens exert masculinizing or feminizing effects in the body respectively, whereas progestogens mainly affect the uterus in preparation for and during pregnancy (Figure 6.1).
While the testes continuously produce spermatozoa and testosterone from puberty (ca. 13 years) to old age, in the adult female, usually only one ovum is produced approximately every 28 days, and oestrogen/ progesterone secretion occurs cyclically (the menstrual cycle) until the menopause, when the ovarian cycle ceases.
