The average baby is about one foot, eight inches long at birth. Over the next twenty years, man will triple the length of the body he was born with and will reach an average height of about five feet, eight inches. However, why don't human beings keep on growing?

    In the body there are of glands called the endocrines, which control our growth. The endocrine glands are: the thyroid in the neck, the pituitary attached to the brain, the thymus in the chest and the sex glands. The pituitary gland is the one that stimulates our bones to grow. If this works too hard, our arms and legs would grow too long and our hand and feet too big. If the gland doesn't work hard enough, we would end up under-sized.

    We continue to grow, but only slightly, after the age 25 and we reach our maximum height between the ages of 35 and 40. After that, we shrink about half an inch every ten years. The reason for this is the drying-up of the cartilages in our joints and in the spinal column as we get older.

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