Puberty

Puberty represents the process of moving from reproductive immaturity to maturity (Alsaker, 1996). Changes occur with respect to overall body stature [Page 424]and composition, hormone levels, and the development of primary and secondary sex characteristics. This process can take two to six years to complete; four years is considered average. Whereas puberty is considered one of the true universals of human development, one of its hallmarks is the tremendous variability that exists between and within individual adolescents. Furthermore, although puberty is seen as a predominantly biological event, the changes it brings interact in a variety of ways with aspects of the adolescent's environment, and can significantly impact other aspects of development and functioning (Alsaker, 1996; Dubas & colleagues, 1991).

Slap (1986) provides a comprehensive accounting of the physical and physiological changes females and males experience during puberty. In females, the onset of puberty is typically marked by the appearance of breast buds and the beginning of the height spurt. The average age for these events is 10 years, with a typical age range of 8 to 13 years for both. Breast development is typically completed by 14 years and adult stature is achieved by an average age of 13 years, with a normal range for both of 10 to 16 years. Pubic hair begins to appear around 10.5 years on average, with a range of 8 to 14 years, and is typically completed by 14.5 years, with a range of 14 to 15 years. The average age of menarche is 12.5 years, with a range of 10.5 to 15.5 years.

In males, the testes begin to enlarge at an average age of 11.5 years, with a range of 9.5 to 13.5 years. Enlargement of the penis and the appearance of pubic hair begin at an average age of 12 years, with a range of 10 to 15 years; penile growth is completed at an average age of 14.5 years, with a range of 12.5 to 16 years, and pubic hair growth is completed at 15.5 years, with a range of 14 to 17 years. First ejaculation (semenarche or spermarche), usually in the context of a nocturnal emission (“wet dream”), occurs at an average age of 13 years, with a range of 12 to 16 years. The average age for the beginning of the height spurt is 12.5 years, with a range of 10.5 to 16 years; adult stature is reached at an average age of 15.5 years, with a range of 13.5 to 17.5 years. The appearance of facial hair and deepening of the voice begin at an average age of 14 years, with a range of 12.5 to 15.5 years.

Multiple factors must be appreciated when trying to understand adolescents' reactions to puberty. Boys generally feel more positive about their changes than girls do; girls tend to be more ambivalent, experiencing a mix of anxiety, excitement, and pride. The amount of information about and preparation for the respective changes is an important predictor of positive adjustment. Girls who are not prepared for menarche and boys who are not prepared for semenarche often experience undue anxiety and shame. Cultural standards of physical attractiveness for males versus females and the fact that adolescents' pubertal body changes are said to have “social stimulus value” (meaning that others notice the changes and react to them) also come into play. For example, puberty brings an increase in lean body mass (i.e., muscle) for males, but a decrease in lean body mass (and an increase in body fat) for females. Depending on the degree to which these normal changes in body shape and composition occur for boys versus girls, the adolescent's body image and overall self-esteem may be enhanced or diminished.

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