Now let's turn to specific facts about sex. In this chapter I'll tell you about girls and women, and in the one that follows, about boys and men. You may have seen something of the sex life of domestic animals ; you know where kittens and puppies come from and, even if you live in the city, where calves and lambs come from.

You know that a dog is either a male or a female and that it is easy to tell which, and that the same applies to people. Here now are the details about the sexual system of the woman. As I explain to you, refer to the drawings of a grown woman on the following page and to the more detailed diagram of hier genitals - sexual parts.

The ovaries are where the egg cells (ova) are stored. These two organs are inside the lower part of the abdomen, one on either side and are the shape of a flattened oval and about 1 1/4 to 2 1/2 inches long. When a girl baby is born, her ovaries already contain, in a undeveloped form, tens of thousands of of them will matuture during her lifetime.

But the ovaries are inactive until a girl reaches puberty. Then, around the ages of eleven to fourteen, they begin a monthly process which is repeated more or less regularly until a woman reaches the age of forty-five (or possibly younger) to fifty-five.

During these thirty to forty years, every twenty-one to thirty-five days, a mature egg (ovum) is produced by one or the othery ovary. (The ovaries do not necessarily alternate the task) The egg cell is very small. A row of two hundred would be only about an inch long.

The ovum bursts through the surface of the ovary and enters the fallopian tube just next to it, helped by the tube's fingerlike fringes, called fimbria. This process is called ovulation, and ocassionally some women can feel a twinge in the lower abdomen within a day or so of the time it happens, but not always just when it happens.

After ovulation, the ovum is moved slowly down the fallopian tube toward the uterus (also called the womb, pronounced 'woom'). This organ, located between the ovaries, is pear-shaped and about 3 inches long in a mature female who has not had children.

It is muscular and elastic and can grow and stretch to many times this size, The uterus is the organ in which a baby grows until it is ready to be born, and whose powerful muscles help to push the baby out through the vagina into the world.

Every month or so the uterus prepares for a fertilized egg, an egg which may grow into a baby. It creates a nourishing soft webbing, or velvety lining, of tiny, delicate blood vessels - a perfect place for the egg to grow in.

If an egg is fertilized, it has already started to grow by the time it enters the uterus, about three or four days after it left the ovary. However if an egg is not fertilized, it stays alive for only about twelve to twenty four hours after entering the fallopian tubem and then it breaks up and is absorbed into the body.

In this case, the growing place in the uterus is not needed, and the lining, blood, and blood vessels are discarded through the vagina and out of the body. This monthly event is called Menstruation (when a woman says she is 'having period')

IN NEXT PART LET'S KNOW ABOUT MENSTRUATION