Puberty refers to the period of sexual maturation. Puberty is when the child experiences physical, hormonal, and sexual changes and becomes capable of reproduction. It is associated with rapid growth and the appearance of secondary sexual characteristics.

Adolescence is the period of transition between puberty and adulthood.

When a healthy child is somewhere between 9 and 16 years old, he or she will enter puberty. The exact age depends on factors such as heredity and nutrition and whether the child is a boy or girl. On average, boys enter puberty 2 years later than girls. At this time, the pituitary and hypothalamus glands in the brain (endocrine glands) begin sending out new hormones that trigger the changes of puberty.

Both boys and girls usually experience sudden gains in height and weight. The hormones will regulate and help determine the person's body build (whether the person tends to be tall or short, thin or heavy, and so on).

The hormones also cause secondary sex characteristics and interest in sex. In girls, the ovaries begin to increase production of estrogen and other "female" hormones. In boys, the testicles increase production of testosterone.

The sweat glands become more active. The sweat produced has a slightly different content than when the child was small (it begins to develop more of an odor). Oil glands become more active, and acne may appear.

At this time the importance of personal hygiene becomes apparent and it is important for boys and girls who are beginning to mature to pay attention to regular bathing and other aspects of hygiene. The adolescent may find that an underarm deodorant or antiperspirant becomes necessary.

PUBERTY IN GIRLS
Puberty usually occurs in girls between 9 and 16 years old. The start of menstrual periods (menarche) is one of the most visible signs that a girl is entering puberty. Before having the first menstrual period, the pubescent girl will normally experience:

• rapid growth, especially an increase in height
• breast enlargement
• pubic, armpit, and leg hair growth
• clear or whitish vaginal secretions
• increased hip width

The ovaries increase their production of estrogen and other hormones. This begins the monthly menstrual cycle. Having menstrual periods is only one part of this cycle. Girls are born with a place for babies to grow (the uterus). Next to the uterus are two small glands (the ovaries). The ovaries produce the female hormones and begin to release eggs, which have been stored in the ovaries since birth.

Every month (approximately), an ovary releases one egg. This egg travels along the Fallopian tube, which connects the ovary to the uterus. In about 3 or 4 days the ovum reaches the uterus. During this time, the lining of the uterus (endometrium) begins to thicken by filling with blood and fluid. This happens so that if the ovum is fertilized, it can grow in this thickened lining to produce a baby.

The ovum can become fertilized if unprotected sexual intercourse occurs during this "fertile" time. When a sperm cell (from the man) and an egg (from the woman) join, a pregnancy occurs.

If the egg is not fertilized, it dissolves and the endometrium drains off, out of the uterus through the vagina, causing a menstrual period. In between the menstrual periods, there may be a clear or whitish vaginal discharge. This is normal.

Menstrual cycles occur over about one month (28 to 32 days). At first, the menstrual periods typically are irregular. The girl may go two months between periods, or may have 2 periods in one month. Over time, these will become more regular. The girl may want to keep track of when she has a menstrual period, and how long the period lasts, on a calendar. This can help her to see what her individual pattern is, and can help her predict when she will have the next menstrual period.

Generally, the different phases of the menstrual cycle are not uncomfortable and the majority of girls will not notice any problems. Cramping, when present, is usually mild. Severe menstrual cramping should be evaluated by a physician. There may, however, be other cyclic changes -- for example, just before or during a menstrual period the girl may feel "moody" or emotional, and may feel puffy or swollen. PMS (premenstrual syndrome) may begin to develop, especially as the girl gets older.

In girls, maturation is usually complete by age 17. Subsequently, any increases in height beyond this age are uncommon. Although full physical maturity has been reached educational and emotional maturity remain ongoing processes. It is important to remember that fertility (often present as early as 12 years of age) precedes emotional maturity and pregnancy can, and often does, occur before an adolescent is equipped for parenthood.

PUBERTY IN BOYS
Puberty usually occurs in boys between 13 and 15 years old. Unlike girls, there is no clearcut sign that tells a boy that he has entered puberty. However, boys will normally experience:

• accelerated growth, especially height
• increased shoulder width
• growth of the penis and testicles
• voice changes
• pubic, beard, and armpit hair growth
• nighttime ejaculations (nocturnal emissions; "wet dreams")

There are five stages in the sexual development of boys:

• Stage one is characterized by downy pubic hair that is similar to the hair found on the abdomen.
• Stage two involves enlargement of the scrotum and testes. The enlargement of the scrotum is accompanied by reddening and folding of the skin. The first sparse pubic hair becomes apparent.
• Stage three involves enlargement of the penis. A majority of this developement occurs in the length of the penis, although there may be small changes in the diameter of the shaft. Further enlargement and development of the scrotum and testis takes place and pubic hair thickens. Other changes involving the pubic hair include curling and coarsening in texture.
• These changes continue throughout the fourth stage accompanied by enlargement of the penile glans with thickening of hair in the pubic area.
• Stage five is the completion of sexual maturation. The penis, scrotum and testis are fully matured and are adult-sized. Pubic hair fills the pubic area and extends onto the surface of the thighs and up the abdomen. Increased body hair, voice changes and other physical changes are called the secondary sex characteristics of puberty. They are the consequence of changing hormone levels in the male body.

• accidental injuries (cause approximately 70% of adolescent deaths)
  • motor vehicle accidents
  • drowning
  • poisoning (usually drug overdoses)
• homicide (second leading cause of death)
• suicide (third leading cause of death)
• alcohol intoxication
• substance abuse
• adolescent depression
• sexual experimentation
• adolescent pregnancy
• sexually transmitted diseases
• malnutrition, anorexia nervosa, bulimia
• childhood stress