7.9: Puberty

Adolescence is often defined as the period that begins with puberty and ends with the transition to adulthood. The commonly accepted beginning age for this period of development is age 12. When adolescence ends is harder to pin down. When does adulthood truly begin? Are we an adult at 18 years of age? Or 20? Or 26 when the brain is said to be fully developed?

Adolescence physical development has evolved historically, with evidence indicating that this stage is lengthening as individuals start puberty earlier and transition to social adulthood later than in the past. Puberty today begins, on average, at age 10–11 years for girls and 11–12 years for boys. This average age of onset has decreased gradually over time since the 19th century by 3–4 months per decade, which has been attributed to a range of factors including better nutrition, obesity, increased father absence, and other environmental factors (Steinberg, 2013). Completion of formal education, financial independence from parents, marriage, and parenthood have all been markers of the end of adolescence and beginning of adulthood, and all of these transitions happen, on average, later now than in the past.

Before puberty, there are nearly no differences between males and females in the distribution of fat and muscle. During puberty, males grow muscle much faster than females, and females experience a higher increase in body fat. An adolescent’s heart and lungs increase in both size and capacity during puberty; these changes contribute to increased strength and tolerance for exercise.

Figure \(\PageIndex{1}\): An adolescent boy[1]

Figure \(\PageIndex{2}\): An adolescent girl[2]

Physical Changes in Adolescence

Adolescence begins with the onset of puberty, a developmental period in which hormonal changes cause rapid physical alterations in the body, culminating in sexual maturity (Lerner & Steinberg, 2009). For both boys and girls, these changes include a growth spurt in height, growth of pubic and underarm hair, and skin changes (e.g., pimples). Hormones drive these pubescent changes, particularly the increase in testosterone for boys and estrogen for girls.[3]

Figure \(\PageIndex{3}\): Puberty brings dramatic changes in the body, including the development of primary and secondary sex characteristics such as enlarged adam’s apple, facial hair, broad shoulders, increased body hair, mature genital organs and more muscular body in males; and mature breasts, broader hips in females; and pubic hair in both.[5]

Typically, the growth spurt is followed by the development of sexual maturity. Sexual changes are divided into two categories: Primary sexual characteristics and secondary sexual characteristics. Primary sexual characteristics are changes in the reproductive organs. For males, this includes growth of the testes, penis, scrotum, and spermarche or first ejaculation of semen. This occurs around 9-14 years old (Breehl & Caban, 2020). For females, primary characteristics include growth of the uterus and menarche or the first menstrual period. The female gametes, which are stored in the ovaries, are present at birth, but are immature. Each ovary contains about 400,000 gametes, but only 500 will become mature eggs (Crooks & Baur, 2007). Beginning at puberty, one ovum ripens and is released about every 28 days during the menstrual cycle. Stress and a higher percentage of body fat can bring menstruation at younger ages. According to , puberty begins on average for girls around 8-13 years old with African American girls starting puberty earlier at around 6 years old.

Figure \(\PageIndex{4}\):Males often start shaving during puberty.[6]

Hormones that are also responsible for sexual development can also wreak havoc on the teenage skin. Acne is an unpleasant consequence of the hormonal changes in puberty. Acne is defined as pimples on the skin due to overactive sebaceous (oil-producing) glands (Dolgin, 2011). These glands develop at a greater speed than the skin ducts that discharge the oil. Consequently, the ducts can become blocked with dead skin and acne will develop. According to the University of California at Los Angeles Medical Center (2000), approximately 85% of adolescents develop acne, and boys develop acne more than girls because of greater levels of testosterone in their systems (Dolgin, 2011). [7]

A major milestone in puberty for girls is menarche, the first menstrual period, typically experienced at around 12 or 13 years of age (Anderson, Dannal, & Must, 2003). The age of menarche varies substantially and is determined by genetics, as well as by diet and lifestyle, since a certain amount of body fat is needed to attain menarche. Girls who are very slim, who engage in strenuous athletic activities, or who are malnourished may begin to menstruate later. Even after menstruation begins, girls whose level of body fat drops below the critical level may stop having their periods.

The sequence of events for puberty is more predictable than the age at which they occur. Some girls may begin to grow pubic hair at age 10 but not attain menarche until age 15.[8]

Male Anatomy

Males have both internal and external genitalia that are responsible for procreation and sexual intercourse. Males produce their sperm on a cycle (that for an individual sperm takes 64 days), and unlike the female's ovulation cycle, the male sperm production cycle is constantly producing millions of sperm daily. The male sex organs are the penis and the testicles, the latter of which produce semen and sperm. The semen and sperm, as a result of sexual intercourse, can fertilize an ovum in the female's body; the fertilized ovum (zygote) develops into a fetus, which is later born as a child.

Figure \(\PageIndex{5}\): The male reproductive system consists of ligaments (suspensory of penis, puboprostatic), perineal membrane, external urethral sphincter, penis, corpus cavernosum, glans penis, foreskin, urethral opening, seminal vesicles, ejaculatory duct, prostate and cowpers glands, vas deferens, testes and scrotum.[9]

Female Anatomy

Female external genitalia is collectively known as the vulva, which includes the mons veneris, labia majora, labia minora, clitoris, vaginal opening, and urethral opening. Female internal reproductive organs consist of the vagina, uterus, fallopian tubes, and ovaries. The uterus hosts the developing fetus, produces vaginal and uterine secretions, and passes the male's sperm through to the fallopian tubes while the ovaries release the eggs. A female is born with all her eggs already produced. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the fallopian tubes. Females have a monthly reproductive cycle; at certain intervals the ovaries release an egg, which passes through the fallopian tube into the uterus. If, in this transit, it meets with sperm, the sperm might penetrate and merge with the egg, fertilizing it. If not fertilized, the egg and the tissue that was lining the uterus is flushed out of the system through menstruation (around every 28 days).

Figure \(\PageIndex{6}\): The female reproductive system is primarily internal and includes the ovaries, uterus, fornix, cervix, vagina, clitoris, labium minus, labium majus and greater vestibular gland.[10]

Effects of Puberty on Development

The age of puberty is getting younger for children throughout the world. A century ago the average age of a girl’s first period in the United States and Europe was 16, while today it is around 13. Because there is no clear marker of puberty for boys, it is harder to determine if boys are maturing earlier, too. In addition to better nutrition, the less positive reasons associated with early puberty for girls include increased stress, obesity, and endocrine disrupting.

Because rates of physical development vary so widely among teenagers, puberty can be a source of pride or embarrassment. Girls and boys who develop more slowly than their peers may feel self-conscious about their lack of physical development; some research has found that negative feelings are particularly a problem for late maturing boys, who are at a higher risk for depression and conflict with parents (Graber et al., 1997) and more likely to be bullied (Pollack & Shuster, 2000). Additionally, problems are also more likely to occur when the child is among the first in his or her peer group to develop. Because the preadolescent time is one of not wanting to appear different, early developing children stand out among their peer group and gravitate toward those who are older (Weir, 2016).

Early maturing boys tend to be physically stronger, taller, and more athletic than their later maturing peers; this can contribute to differences in popularity among peers, which can in turn influence the teenager’s confidence. Some studies show that boys who mature earlier tend to be more popular and independent but are also at a greater risk for substance abuse and early sexual activity (Flannery, Rowe, & Gulley, 1993; Kaltiala-Heino, Rimpela, Rissanen, & Rantanen, 2001).

Early maturing girls may face increased teasing and sexual harassment related to their developing bodies, which can contribute to self-consciousness and place them at a higher risk for anxiety, depression, substance abuse, and eating disorders (Ge, Conger, & Elder, 2001; Graber, Lewinsohn, Seeley, & Brooks-Gunn, 1997; Striegel-Moore & Cachelin, 1999).[11]

Stress and elevated levels of cortisol are associated with earlier puberty, especially in girls (Belsky et al., 2015). Racial microaggressions and minority stress take a toll on the body and influence mental and physical health at the intersection of race and gender (Lewis et al., 2017). In addition to most research being conducted on White girls and when they reach puberty, other health outcomes that disproportionately impact Black girls have not been researched enough (Salsbury et al., 2009). While puberty for girls of all races and ethnicities has been decreasing over the past several years, Black girls “have the lowest median age of menarche and the highest rate of childhood obesity” (Salsbury et al., 2009, p. 2). Latina youth also start puberty earlier due to similar impacts of stress and higher body mass indexes (BMIs) at a younger age (Jean et al., 2009). Something to keep in mind, research based on race and ethnic differences in pubertal timing are still very limited and it is important to question the notion of what constitutes normative BMI, especially when studies are conducted on mostly White populations. Additionally, while the timing of puberty has significant social implications which then impacts self-esteem, this interaction is also context-dependent and based on many intersecting and complex factors. Every single person may have a different experience related to puberty due to the way peers treat them and the messages they receive from the media, teachers, family, religious institutions, and more about this process.

Precocious and Delayed Puberty

If a girl begins puberty before age 8 and boys before age 9, then they would be considered to have precocious (or early) puberty (National Institute of Child Health and Human Development [NICHD], 2016). Some children may experience psychological and social problems related to feeling different than their peers (NICHD, 2016). Boys are less likely to experience negative consequences, such as bullying, if they develop earlier. Individuals who develop earlier may be perceived by others as more mature and older than they are developmentally. Thus, girls may face greater levels of sexualization earlier and boys may experience reduced levels of bullying due to their size and increased body mass.

Delayed puberty is when a girl experiences a lack of breast growth by age 13 or the lack of a period (menarche) by age 16 (Tang et al., 2020). For boys, this is when testicular enlargement has not occurred by age 14 (Tang et al., 2020). Girls and boys may experience bullying from peers due to their smaller and more child-like appearance. Boys in particular may face heightened levels of bullying and negative self-esteem consequences.

Context is Important

According to the literature review conducted by Seaton & Carter (2018), “Given ethnic/racial variations in standards of physical attractiveness, being a member of a racial group can influence body image norms. African American girls tend to describe their beauty ideals in terms of personality characteristics such as style, attitude, pride, and confidence; whereas White girls tend to describe their beauty ideals in terms of fixed physical attributes such as tall, thin, and high cheekbones… Researchers have speculated that adolescent girls who adopt body ideals in terms of personality characteristics are less vulnerable to the distress generated by puberty” (p. 42). Seaton & Carter (2018) found in their research that Black girls who view their racial identity as more central to their sense of self will experience more distress if they enter puberty later, especially if they attend a school that is predominately White. Late developing Black girls also may be further bullied by peers, so earlier puberty could act as a protection against racialized microaggressions since early maturing girls are perceived as more mature and advanced by peers within the school context (Seaton & Carter, 2018).

Jean et al. (2009) explored family dynamics and differences in acculturation between younger and older generations of Mexican Americans. The researchers found that mothers who immigrated to the United States in adulthood viewed their body size more favorably compared to their daughters who grew up attending school in the United States. Fathers were also generally very supportive of their daughters’ weight and size. Based on interviews with the girls compared to their parents, acculturation caused internalized beauty ideals that favored thinness and height more than that of their mothers and fathers. The length of time in the United States was associated with peer influence shaping standards of beauty more than family. Therefore, generational differences and acculturation can also influence body image and self-esteem. The girls who resisted acculturation actually showed more body satisfaction as their bodies began to change due to puberty when compared to the girls who internalized more American beauty standards (Jean et al., 2009).

Hormone Blockers for Transgender Individuals

An area of debate is whether transgender youth should be able to take hormone blockers prior to and during puberty in conjunction with hormone therapy in order to prevent unwanted changes during puberty and to bring about a puberty that more closely matches that of their gender identity because our society heavily correlates physical features with gender. For example, testosterone acts on the vocal cords to deepen the voice and body mass begins to redistribute which can be distressing to some transgender girls. Hormone blockers would prevent this process from occurring. However, some people argue that children cannot make such serious decisions for themselves and legally parents or guardians are the ones who consent to medical care on their youths’ behalf. This commonly results in a person needing to wait until they can consent to medical care for themselves before they can receive hormone therapy. At this point, puberty has already made lasting changes to the body that will take greater levels of medical intervention to alter.

Turban et al. (2020) and Achille et al. (2020) found that transgender youth who wanted and were provided with pubertal suppression hormones experienced a significant decrease in suicidal ideation, depression, and anxiety and reported improved overall mental health. According to Turban et al. (2020), the Endocrine Society guidelines and the World Professional Association for Transgender Health (WPATH) Standards of Care both recommend that transgender adolescents be offered puberty blockers, which are formally called gonadotropin-releasing hormone analogues (GnRHas).

Attributions:

Child Growth and Development by Jennifer Paris, Antoinette Ricardo, and Dawn Rymond, 2019, is licensed under CC BY 4.0

Above adapted heavily with information from the following.

Introduction to Human Sexuality by Ericka Goerling & Emerson Wolfe is licensed under CC BY-NC-SA 4.0

[1] Image on Pixabay

[2] Image on Pixabay

[3] Adolescent Development by Jennifer Lansford is licensed under CC BY-NC-SA 4.0

[4] Adolescence: Developing Independence and Identity by Charles Stangor is licensed under CC BY-NC-SA 3.0

[5] Image by the Open University of Hong Kong is licensed under CC BY-SA 4.0

[6] Image by Antiporda Productions is licensed under CC BY 2.0

[7] Lifespan Development: A Psychological Perspective by Martha Lally and Suzanne Valentine-French is licensed under CC BY-NC-SA 3.0

[8] Beginning Psychology - Growing and Developing by Charles Stangor is licensed under CC BY-NC-SA 3.0

[9] Image is in the public domain

[10] Image by BruceBlaus is licensed under CC BY-SA 3.0

[11] Adolescence Physical Growth by Boundless.com is licensed under CC BY-SA 4.0; Lifespan Development: A Psychological Perspective by Martha Lally and Suzanne Valentine-French is licensed under CC BY-NC-SA 3.0