Chapter Introduction

CHAPTER 14
Adolescence: Biosocial Development

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What Will You Know?

  1. How can you predict when puberty will begin for a particular child?

    If a child's genes, gender, body fat, and stress levels are known, it is possible to predict timing of puberty. Genetic differences among ethnic groups lead African Americans to reach puberty earliest and Chinese Americans to reach puberty latest. Northern European girls reach menarche earlier than southern European girls. Girls reach puberty on average two years earlier than boys. Heavier girls reach puberty years earlier than malnourished girls do; 100 pounds appears to be the critical minimum weight for menarche to occur. Heavier boys reach puberty later than boys who are closer to their ideal weight. Body fat produces leptin, which is necessary for the onset of puberty. Stress hastens the onset of puberty.

  2. Why do some teenagers avoid eating for days, even months?

    Many teenagers are unhappy with their bodies, in part because few look like the bodies portrayed in the media. Dissatisfaction with body image can be dangerous, leading to eating disorders such as anorexia and binge eating. Anorexia is particularly common among high–achieving, upper–class young women.

  3. What makes teenage sex a problem instead of a joy?

    Teenage sexual activity presents risks, including pregnancy and sexually transmitted infections. When young teenagers have sex, they are at greater risk for depression and drug abuse.

  1. Puberty Begins

    Unseen Beginnings

    opposing perspectives: Algebra at 7 a.m.? Get Real!

    Age and Puberty

    a view from science: Stress and Puberty

    Too Early, Too Late

  2. Growth and Nutrition

    Growing Bigger and Stronger

    Diet Deficiencies

    Eating Disorders

  3. Brain Development

    a case to study: “What Were You Thinking?”

    Benefits of Adolescent Brain Development

  4. Sexual Maturation

    Sexual Characteristics

    Sexual Activity

    Sexual Problems in Adolescence

I overheard a conversation among three teenagers, including my daughter Rachel, all of them past their awkward years and now becoming beautiful. They were discussing the imperfections of their bodies. One spoke of her fat stomach (what stomach? I could not see it), another of her long neck (hidden by her silky, shoulder-length hair). Rachel complained not only about a bent pinky finger but also about her feet!

The reality that children grow into men and women is no shock to any adult. But for teenagers, heightened self-awareness often triggers surprise or even horror, joy, and despair at the specifics of their development. Like these three, adolescents pay attention to details of their growth. Gender differences also become prominent. Girls tend to bond as they discuss their flaws; boys are more likely to boast than to complain, yet almost all teenagers become simultaneously self-conscious and social, needing each other for validation.

This chapter describes the biosocial specifics of growing bodies and emerging sexuality. It all begins with hormones, but other invisible changes may be even more potent—such as the timing of neurological maturation that does not yet allow adolescents like these three to realize that minor imperfections are insignificant.