=The external genitalia=, sometimes called the _vulva_, really have nothing to do with the creation of the baby, but you will better understand some of the care that is given you if you know a little about them, too. Between the thighs, where they join the body, are two thick folds of flesh, called the _labia_ and between these lie the perineum, just mentioned, and the openings from the rectum, vagina and bladder as shown in Fig. 2. Now that we have something of an idea of the structure of the organs concerned with the creation of the baby, we shall want to learn about the usual activities of these interesting little parts, before the baby begins his life within them. =Puberty or Adolescence.= You know, of course, that girls are incapable of becoming mothers until after what is termed puberty, or adolescence, and by these terms we mean the period during which childhood develops into sexual maturity, and the individual becomes capable of reproduction. The age at which puberty occurs varies with climate, race and occupation and with different individuals of the same status. But the average for girls, in temperate climates, is from the twelfth to the sixteenth year and for boys from the fourteenth to the seventeenth year. Girls in southern climates sometimes mature as early as the eighth or ninth year while in colder regions puberty may be delayed until they are eighteen or twenty years old. The occurrence of puberty marks the establishment of _ovulation_ and _menstruation_, two functions which are usually performed once a month during the childbearing period.