Adolescence is the stage of development that turns children into adults. Adolescence in boys usually begins around the age of 10, although occasionally it will be earlier, and in some cases later: Each child develops at his own rate, some more quickly and some more slowly. There is usually no need for concern unless puberty begins before age 8 or has not yet started by 15.
The following is a list of the changes that occur in boys' bodies in the usual order in which they appear. Once again, it is important to remember that each boy is different and there is a great deal of variety in the age at which these changes begin and end.
In general, the first physical change for boys is growth of the testicles. This generally starts around age 10 and may go unnoticed. Approximately a year later, the boy's penis will begin to grow longer, and in time it will thicken as well. There will be growth spurts as the boy becomes taller and wider. In many cases, the hands and feet grow before the rest of the body, leaving the boy "gangly" (and often clumsy). The shoulders begin to widen. Pubic hair starts growing just after 13 years of age. As the hormones take hold, boys of about 14 will begin to have erections and may have wet dreams. They start getting hairier; underarm and facial hair begins to be noticeable by 15. At approximately this stage, they will also begin to sweat more and may develop acne. Boys' voices change at this age, too; sometimes quite suddenly, sometimes going through a period of "breaking." They may develop an Adam's apple. Adolescent males usually reach their full height and complete physical development by age 18.
During this time, psychological changes also take place, leading to more maturity and independence. Adolescents are more able to think abstractly, and they start to consider long-term consequences. Thinking about relationships and sex begins during this stage as their brains begin to catch up to the development of their bodies.