Justin J. Lehmiller, PhD, is a social psychologist and Research Fellow at the Kinsey Institute at Indiana University. He hosts the popular Sex and Psychology Podcast and is author of the bestselling book Tell Me What You Want: The Science of Sexual Desire and How It Can Help You Improve Your Sex Life.

• About the Author xiForeplay xiiList of Illustrations xivList of Text Boxes xxiList of Tables xxiiiAbout the Companion Website xxiv1 Theoretical Perspectives on Human Sexuality 1Introduction 2What Drives Us to Have Sex? 2Psychological Influences 2Cultural, Societal, and Environmental Influences 3Biological and Evolutionary Influences 6Major Theoretical Perspectives on Human Sexuality 7Psychoanalytic Theory 7Cognitive-Behavioral and Learning Theories 8Exchange Theories 12Personality Theories 12Evolutionary Theory 15The Perspective of This Text 16Key Terms 18Discussion Questions: What Is Your Perspective on Sex? 18References 182 Sexology Research: History, Methods, and Ethics 21Introduction 22A Brief History of Sexology 22Hidden Figures in Sexology 25Sexology as a Science 26Sample Selection 27Nonexperimental Research 28Surveys 28Direct Observation 31Case Reports 35Experimental Research 35A Sample Sexperiment 35Strengths and Limitations of the Experimental Method 36A Note on Statistics 36Means and Medians 36Incidence and Prevalence 37Correlation 37Ethics in Sexology Research 38Informed Consent 40Debriefing 40Confidentiality 41How Reliable Are the Results of Sex Studies? 42Evaluating Sex Research 42Key Terms 43Discussion Questions: What Is Your Perspective on Sex? 43References 433 Human Sexual Anatomy 46Introduction 47Anatomy of the Penis 47A Historical and Cultural Overview of the Penis 47External Anatomy 48Internal Anatomy 52Psychology of the Penis: Genital Concerns 54Genital Health Issues 55Anatomy of the Vulva 56A Historical and Cultural Overview of the Vulva 56External Anatomy 56Internal Anatomy 60Breasts 62Psychology of the Breasts and Vulva: Bodily Concerns 63Breast and Genital Health Issues 65Conclusions 68Key Terms 68Discussion Questions: What Is Your Perspective on Sex? 68References 684 Human Sexual Response: Understanding Arousal and Orgasm 72Introduction 73Factors That Influence Sexual Arousal 73The Brain 73The Senses 74Hormones 81Substances 84The Sexual Response Cycle 87The Masters and Johnson Model 87Psychological Models of Sexual Response 92Key Terms 93Discussion Questions: What Is Your Perspective on Sex? 93References 945 Gender and Gender Identity 98Introduction 98Biological Influences on Gender Identity and Sexuality 100Biological Sex Variations 101Psychosocial Influences on Gender Identity and Sexuality 106Social Interactions and Norms 106Physical Environments 107Media 108Gender Diversity: Variations in Gender Expression 108Transgender Persons and Gender Dysphoria 110Cross-Dressing 115Other Gender Diverse Identities 116Just How Different Are Men and Women? 116Sex Differences in Psychology 116Sex Differences in Sexuality and Attitudes Toward Sex 117Key Terms 118Discussion Questions: What is Your Perspective on Sex? 118References 1186 Sexual Orientation 123Introduction 124Sexual Orientation: Definitions and Types 124Measurement and Prevalence 125Theories of Sexual Orientation 128Early Psychological Theories 128Biological and Hormonal Theories 129Evolutionary Theories 131Biopsychosocial Theories 132Sex Differences in the Expression of Sexual Orientation 135Sexual Orientation Attitudes 137Prejudice Against Sexual Minority Persons 137Sexual Orientation in Psychological Perspective 140Sexual Orientation Myths 142Key Terms 144Discussion Questions: What is Your Perspective on Sex? 145References 1457 The Laws of Attraction 149Introduction 150What Attracts us to Other People? 150Affective/Mood Influences 151Propinquity 153Similarity 154Scarcity 156Physiological Arousal 157Neurochemical Factors 158Physical Attractiveness 158Other Factors Involved in Attraction 159Attraction Processes among LGBTQ+ Persons 160Why are Men and Women Attracted to Different Characteristics? 161Evolutionary Theory 161Social Structural Perspectives 164Key Terms 167Discussion Questions: What Is Your Perspective on Sex? 167References 1678 Intimate Relationships: Sex, Love, and Commitment 171Introduction 172Singlehood and Casual Relationships 172Sexuality Among Singles 172Hookups 174Friends with Benefits 174Singles’ Sexual Outcomes 175Love and Committed Relationships 177The Nature of Love 177The Nature of Commitment 181Varieties of Loving and Committed Relationships 183What Makes a Relationship Last? 188Characteristics of Good Relationships 188The Dark Side of Relationships 191Coping with Breakup 195Key Terms 195Discussion Questions: What Is Your Perspective on Sex? 196References 1969 Sexual Behaviors 201Introduction 202Solitary Sexual Behaviors 202Asexuality and Celibacy 202Sexual Fantasy 204Masturbation 207Partnered Sexual Behaviors 210Kissing 211Touching 212Oral Sex 213Vaginal Intercourse 213Anal Sex 214LGBTQ+ Sexual Behaviors 215Sex with Three, or Four, or More 216Frequency and Benefits of Sex and Orgasm 218Sexual Behavior in Psychological Perspective 220Self-Regulation 220Attachment Style 221Mortality Salience 222Key Terms 222Discussion Questions: What Is Your Perspective on Sex? 222References 22310 Lifespan Sexual Development 227Introduction 228Sexual Development from Infancy Through Adolescence 228Infancy and Childhood 228Puberty 230Adolescence 231Biopsychosocial Influences on Teenage Sexual Activity 234Implications of Early or Late Sexual Development 236Sexuality and Aging 237Biopsychosocial Influences on the Sexual Activities of Older Adults 240Key Terms 242Discussion Questions: What Is Your Perspective on Sex? 242References 24311 Sex Education, Contraception, and Pregnancy 246Introduction 247Sex Education 247Sex Education in Cross-Cultural Perspective 251Contraception 252History 252Types of Contraceptives 253Choosing the Right Contraceptive 261Pregnancy 261The Psychology of Trying to Have a Baby 261Psychological Changes during Pregnancy and after Birth 262Abortion 263Key Terms 264Discussion Questions: What Is Your Perspective on Sex? 264References 26412 Sexually Transmitted Infections and Safer-Sex Practices 268Introduction 269Sexually Transmitted Infections 269Bacterial Infections 270Viral Infections 272Other Infections 277Factors that Increase the Spread of STIs 277Biological 277Psychological 278Social and Environmental 279The Psychological Impact of STIs 281Implications for Romantic and Sexual Relationships 281Preventing Infection 282Key Terms 284Discussion Questions: What Is Your Perspective on Sex? 285References 28513 Sexual Dysfunction and Sex Therapy 288Introduction 289Causes of Sex Difficulties 289Biological 289Psychological 290Social 292Types of Sexual Dysfunction 293Desire Problems 293Arousal Problems 296Orgasm Problems 296Pain Disorders 297Sex Therapy 298Schools of Thought 298Specific Treatments 301Tips for Avoiding Sexual Difficulties 306Key Terms 307Discussion Questions: What Is Your Perspective on Sex? 307References 30714 Variations in Sexual Behavior 311Introduction 312What Are Paraphilias? 312Types of Paraphilias 313Fetishism 314Transvestism/Erotic Cross-Dressing 317Sadomasochism 318Voyeurism 319Exhibitionism 321Pedophilia 322Other Paraphilias 323Paraphilia Controversies 327Treatment of Paraphilic Disorders 327Medical Therapies 327Psychological Therapies 328Social Skills Training 328Effectiveness 328Key Terms 329Discussion Questions: What Is Your Perspective on Sex? 329References 32915 Sex Laws, Sexual Victimization, and the Sexual Marketplace 332Introduction 333A Brief History of Sex Laws 333Sexual Consent 334Nonconsensual Sex: Sexual Coercion and Violence 335Sexual Assault 335Child Sexual Abuse 337Sexual Harassment 339The Sexual Marketplace 341Prostitution 341Sex Trafficking 344Pornography 345Key Terms 353Discussion Questions: What Is Your Perspective on Sex? 353References 353Epilogue 357Glossary 358Index 367

Justin J. Lehmiller, PhD, is a social psychologist and Research Fellow at the Kinsey Institute at Indiana University. He hosts the popular Sex and Psychology Podcast and is author of the bestselling book Tell Me What You Want: The Science of Sexual Desire and How It Can Help You Improve Your Sex Life.

• About the Author xiForeplay xiiList of Illustrations xivList of Text Boxes xxiList of Tables xxiiiAbout the Companion Website xxiv1 Theoretical Perspectives on Human Sexuality 1Introduction 2What Drives Us to Have Sex? 2Psychological Influences 2Cultural, Societal, and Environmental Influences 3Biological and Evolutionary Influences 6Major Theoretical Perspectives on Human Sexuality 7Psychoanalytic Theory 7Cognitive-Behavioral and Learning Theories 8Exchange Theories 12Personality Theories 12Evolutionary Theory 15The Perspective of This Text 16Key Terms 18Discussion Questions: What Is Your Perspective on Sex? 18References 182 Sexology Research: History, Methods, and Ethics 21Introduction 22A Brief History of Sexology 22Hidden Figures in Sexology 25Sexology as a Science 26Sample Selection 27Nonexperimental Research 28Surveys 28Direct Observation 31Case Reports 35Experimental Research 35A Sample Sexperiment 35Strengths and Limitations of the Experimental Method 36A Note on Statistics 36Means and Medians 36Incidence and Prevalence 37Correlation 37Ethics in Sexology Research 38Informed Consent 40Debriefing 40Confidentiality 41How Reliable Are the Results of Sex Studies? 42Evaluating Sex Research 42Key Terms 43Discussion Questions: What Is Your Perspective on Sex? 43References 433 Human Sexual Anatomy 46Introduction 47Anatomy of the Penis 47A Historical and Cultural Overview of the Penis 47External Anatomy 48Internal Anatomy 52Psychology of the Penis: Genital Concerns 54Genital Health Issues 55Anatomy of the Vulva 56A Historical and Cultural Overview of the Vulva 56External Anatomy 56Internal Anatomy 60Breasts 62Psychology of the Breasts and Vulva: Bodily Concerns 63Breast and Genital Health Issues 65Conclusions 68Key Terms 68Discussion Questions: What Is Your Perspective on Sex? 68References 684 Human Sexual Response: Understanding Arousal and Orgasm 72Introduction 73Factors That Influence Sexual Arousal 73The Brain 73The Senses 74Hormones 81Substances 84The Sexual Response Cycle 87The Masters and Johnson Model 87Psychological Models of Sexual Response 92Key Terms 93Discussion Questions: What Is Your Perspective on Sex? 93References 945 Gender and Gender Identity 98Introduction 98Biological Influences on Gender Identity and Sexuality 100Biological Sex Variations 101Psychosocial Influences on Gender Identity and Sexuality 106Social Interactions and Norms 106Physical Environments 107Media 108Gender Diversity: Variations in Gender Expression 108Transgender Persons and Gender Dysphoria 110Cross-Dressing 115Other Gender Diverse Identities 116Just How Different Are Men and Women? 116Sex Differences in Psychology 116Sex Differences in Sexuality and Attitudes Toward Sex 117Key Terms 118Discussion Questions: What is Your Perspective on Sex? 118References 1186 Sexual Orientation 123Introduction 124Sexual Orientation: Definitions and Types 124Measurement and Prevalence 125Theories of Sexual Orientation 128Early Psychological Theories 128Biological and Hormonal Theories 129Evolutionary Theories 131Biopsychosocial Theories 132Sex Differences in the Expression of Sexual Orientation 135Sexual Orientation Attitudes 137Prejudice Against Sexual Minority Persons 137Sexual Orientation in Psychological Perspective 140Sexual Orientation Myths 142Key Terms 144Discussion Questions: What is Your Perspective on Sex? 145References 1457 The Laws of Attraction 149Introduction 150What Attracts us to Other People? 150Affective/Mood Influences 151Propinquity 153Similarity 154Scarcity 156Physiological Arousal 157Neurochemical Factors 158Physical Attractiveness 158Other Factors Involved in Attraction 159Attraction Processes among LGBTQ+ Persons 160Why are Men and Women Attracted to Different Characteristics? 161Evolutionary Theory 161Social Structural Perspectives 164Key Terms 167Discussion Questions: What Is Your Perspective on Sex? 167References 1678 Intimate Relationships: Sex, Love, and Commitment 171Introduction 172Singlehood and Casual Relationships 172Sexuality Among Singles 172Hookups 174Friends with Benefits 174Singles’ Sexual Outcomes 175Love and Committed Relationships 177The Nature of Love 177The Nature of Commitment 181Varieties of Loving and Committed Relationships 183What Makes a Relationship Last? 188Characteristics of Good Relationships 188The Dark Side of Relationships 191Coping with Breakup 195Key Terms 195Discussion Questions: What Is Your Perspective on Sex? 196References 1969 Sexual Behaviors 201Introduction 202Solitary Sexual Behaviors 202Asexuality and Celibacy 202Sexual Fantasy 204Masturbation 207Partnered Sexual Behaviors 210Kissing 211Touching 212Oral Sex 213Vaginal Intercourse 213Anal Sex 214LGBTQ+ Sexual Behaviors 215Sex with Three, or Four, or More 216Frequency and Benefits of Sex and Orgasm 218Sexual Behavior in Psychological Perspective 220Self-Regulation 220Attachment Style 221Mortality Salience 222Key Terms 222Discussion Questions: What Is Your Perspective on Sex? 222References 22310 Lifespan Sexual Development 227Introduction 228Sexual Development from Infancy Through Adolescence 228Infancy and Childhood 228Puberty 230Adolescence 231Biopsychosocial Influences on Teenage Sexual Activity 234Implications of Early or Late Sexual Development 236Sexuality and Aging 237Biopsychosocial Influences on the Sexual Activities of Older Adults 240Key Terms 242Discussion Questions: What Is Your Perspective on Sex? 242References 24311 Sex Education, Contraception, and Pregnancy 246Introduction 247Sex Education 247Sex Education in Cross-Cultural Perspective 251Contraception 252History 252Types of Contraceptives 253Choosing the Right Contraceptive 261Pregnancy 261The Psychology of Trying to Have a Baby 261Psychological Changes during Pregnancy and after Birth 262Abortion 263Key Terms 264Discussion Questions: What Is Your Perspective on Sex? 264References 26412 Sexually Transmitted Infections and Safer-Sex Practices 268Introduction 269Sexually Transmitted Infections 269Bacterial Infections 270Viral Infections 272Other Infections 277Factors that Increase the Spread of STIs 277Biological 277Psychological 278Social and Environmental 279The Psychological Impact of STIs 281Implications for Romantic and Sexual Relationships 281Preventing Infection 282Key Terms 284Discussion Questions: What Is Your Perspective on Sex? 285References 28513 Sexual Dysfunction and Sex Therapy 288Introduction 289Causes of Sex Difficulties 289Biological 289Psychological 290Social 292Types of Sexual Dysfunction 293Desire Problems 293Arousal Problems 296Orgasm Problems 296Pain Disorders 297Sex Therapy 298Schools of Thought 298Specific Treatments 301Tips for Avoiding Sexual Difficulties 306Key Terms 307Discussion Questions: What Is Your Perspective on Sex? 307References 30714 Variations in Sexual Behavior 311Introduction 312What Are Paraphilias? 312Types of Paraphilias 313Fetishism 314Transvestism/Erotic Cross-Dressing 317Sadomasochism 318Voyeurism 319Exhibitionism 321Pedophilia 322Other Paraphilias 323Paraphilia Controversies 327Treatment of Paraphilic Disorders 327Medical Therapies 327Psychological Therapies 328Social Skills Training 328Effectiveness 328Key Terms 329Discussion Questions: What Is Your Perspective on Sex? 329References 32915 Sex Laws, Sexual Victimization, and the Sexual Marketplace 332Introduction 333A Brief History of Sex Laws 333Sexual Consent 334Nonconsensual Sex: Sexual Coercion and Violence 335Sexual Assault 335Child Sexual Abuse 337Sexual Harassment 339The Sexual Marketplace 341Prostitution 341Sex Trafficking 344Pornography 345Key Terms 353Discussion Questions: What Is Your Perspective on Sex? 353References 353Epilogue 357Glossary 358Index 367

Justin J. Lehmiller, PhD, is a social psychologist and Research Fellow at the Kinsey Institute at Indiana University. He hosts the popular Sex and Psychology Podcast and is author of the bestselling book Tell Me What You Want: The Science of Sexual Desire and How It Can Help You Improve Your Sex Life.

• About the Author xiForeplay xiiList of Illustrations xivList of Text Boxes xxiList of Tables xxiiiAbout the Companion Website xxiv1 Theoretical Perspectives on Human Sexuality 1Introduction 2What Drives Us to Have Sex? 2Psychological Influences 2Cultural, Societal, and Environmental Influences 3Biological and Evolutionary Influences 6Major Theoretical Perspectives on Human Sexuality 7Psychoanalytic Theory 7Cognitive-Behavioral and Learning Theories 8Exchange Theories 12Personality Theories 12Evolutionary Theory 15The Perspective of This Text 16Key Terms 18Discussion Questions: What Is Your Perspective on Sex? 18References 182 Sexology Research: History, Methods, and Ethics 21Introduction 22A Brief History of Sexology 22Hidden Figures in Sexology 25Sexology as a Science 26Sample Selection 27Nonexperimental Research 28Surveys 28Direct Observation 31Case Reports 35Experimental Research 35A Sample Sexperiment 35Strengths and Limitations of the Experimental Method 36A Note on Statistics 36Means and Medians 36Incidence and Prevalence 37Correlation 37Ethics in Sexology Research 38Informed Consent 40Debriefing 40Confidentiality 41How Reliable Are the Results of Sex Studies? 42Evaluating Sex Research 42Key Terms 43Discussion Questions: What Is Your Perspective on Sex? 43References 433 Human Sexual Anatomy 46Introduction 47Anatomy of the Penis 47A Historical and Cultural Overview of the Penis 47External Anatomy 48Internal Anatomy 52Psychology of the Penis: Genital Concerns 54Genital Health Issues 55Anatomy of the Vulva 56A Historical and Cultural Overview of the Vulva 56External Anatomy 56Internal Anatomy 60Breasts 62Psychology of the Breasts and Vulva: Bodily Concerns 63Breast and Genital Health Issues 65Conclusions 68Key Terms 68Discussion Questions: What Is Your Perspective on Sex? 68References 684 Human Sexual Response: Understanding Arousal and Orgasm 72Introduction 73Factors That Influence Sexual Arousal 73The Brain 73The Senses 74Hormones 81Substances 84The Sexual Response Cycle 87The Masters and Johnson Model 87Psychological Models of Sexual Response 92Key Terms 93Discussion Questions: What Is Your Perspective on Sex? 93References 945 Gender and Gender Identity 98Introduction 98Biological Influences on Gender Identity and Sexuality 100Biological Sex Variations 101Psychosocial Influences on Gender Identity and Sexuality 106Social Interactions and Norms 106Physical Environments 107Media 108Gender Diversity: Variations in Gender Expression 108Transgender Persons and Gender Dysphoria 110Cross-Dressing 115Other Gender Diverse Identities 116Just How Different Are Men and Women? 116Sex Differences in Psychology 116Sex Differences in Sexuality and Attitudes Toward Sex 117Key Terms 118Discussion Questions: What is Your Perspective on Sex? 118References 1186 Sexual Orientation 123Introduction 124Sexual Orientation: Definitions and Types 124Measurement and Prevalence 125Theories of Sexual Orientation 128Early Psychological Theories 128Biological and Hormonal Theories 129Evolutionary Theories 131Biopsychosocial Theories 132Sex Differences in the Expression of Sexual Orientation 135Sexual Orientation Attitudes 137Prejudice Against Sexual Minority Persons 137Sexual Orientation in Psychological Perspective 140Sexual Orientation Myths 142Key Terms 144Discussion Questions: What is Your Perspective on Sex? 145References 1457 The Laws of Attraction 149Introduction 150What Attracts us to Other People? 150Affective/Mood Influences 151Propinquity 153Similarity 154Scarcity 156Physiological Arousal 157Neurochemical Factors 158Physical Attractiveness 158Other Factors Involved in Attraction 159Attraction Processes among LGBTQ+ Persons 160Why are Men and Women Attracted to Different Characteristics? 161Evolutionary Theory 161Social Structural Perspectives 164Key Terms 167Discussion Questions: What Is Your Perspective on Sex? 167References 1678 Intimate Relationships: Sex, Love, and Commitment 171Introduction 172Singlehood and Casual Relationships 172Sexuality Among Singles 172Hookups 174Friends with Benefits 174Singles’ Sexual Outcomes 175Love and Committed Relationships 177The Nature of Love 177The Nature of Commitment 181Varieties of Loving and Committed Relationships 183What Makes a Relationship Last? 188Characteristics of Good Relationships 188The Dark Side of Relationships 191Coping with Breakup 195Key Terms 195Discussion Questions: What Is Your Perspective on Sex? 196References 1969 Sexual Behaviors 201Introduction 202Solitary Sexual Behaviors 202Asexuality and Celibacy 202Sexual Fantasy 204Masturbation 207Partnered Sexual Behaviors 210Kissing 211Touching 212Oral Sex 213Vaginal Intercourse 213Anal Sex 214LGBTQ+ Sexual Behaviors 215Sex with Three, or Four, or More 216Frequency and Benefits of Sex and Orgasm 218Sexual Behavior in Psychological Perspective 220Self-Regulation 220Attachment Style 221Mortality Salience 222Key Terms 222Discussion Questions: What Is Your Perspective on Sex? 222References 22310 Lifespan Sexual Development 227Introduction 228Sexual Development from Infancy Through Adolescence 228Infancy and Childhood 228Puberty 230Adolescence 231Biopsychosocial Influences on Teenage Sexual Activity 234Implications of Early or Late Sexual Development 236Sexuality and Aging 237Biopsychosocial Influences on the Sexual Activities of Older Adults 240Key Terms 242Discussion Questions: What Is Your Perspective on Sex? 242References 24311 Sex Education, Contraception, and Pregnancy 246Introduction 247Sex Education 247Sex Education in Cross-Cultural Perspective 251Contraception 252History 252Types of Contraceptives 253Choosing the Right Contraceptive 261Pregnancy 261The Psychology of Trying to Have a Baby 261Psychological Changes during Pregnancy and after Birth 262Abortion 263Key Terms 264Discussion Questions: What Is Your Perspective on Sex? 264References 26412 Sexually Transmitted Infections and Safer-Sex Practices 268Introduction 269Sexually Transmitted Infections 269Bacterial Infections 270Viral Infections 272Other Infections 277Factors that Increase the Spread of STIs 277Biological 277Psychological 278Social and Environmental 279The Psychological Impact of STIs 281Implications for Romantic and Sexual Relationships 281Preventing Infection 282Key Terms 284Discussion Questions: What Is Your Perspective on Sex? 285References 28513 Sexual Dysfunction and Sex Therapy 288Introduction 289Causes of Sex Difficulties 289Biological 289Psychological 290Social 292Types of Sexual Dysfunction 293Desire Problems 293Arousal Problems 296Orgasm Problems 296Pain Disorders 297Sex Therapy 298Schools of Thought 298Specific Treatments 301Tips for Avoiding Sexual Difficulties 306Key Terms 307Discussion Questions: What Is Your Perspective on Sex? 307References 30714 Variations in Sexual Behavior 311Introduction 312What Are Paraphilias? 312Types of Paraphilias 313Fetishism 314Transvestism/Erotic Cross-Dressing 317Sadomasochism 318Voyeurism 319Exhibitionism 321Pedophilia 322Other Paraphilias 323Paraphilia Controversies 327Treatment of Paraphilic Disorders 327Medical Therapies 327Psychological Therapies 328Social Skills Training 328Effectiveness 328Key Terms 329Discussion Questions: What Is Your Perspective on Sex? 329References 32915 Sex Laws, Sexual Victimization, and the Sexual Marketplace 332Introduction 333A Brief History of Sex Laws 333Sexual Consent 334Nonconsensual Sex: Sexual Coercion and Violence 335Sexual Assault 335Child Sexual Abuse 337Sexual Harassment 339The Sexual Marketplace 341Prostitution 341Sex Trafficking 344Pornography 345Key Terms 353Discussion Questions: What Is Your Perspective on Sex? 353References 353Epilogue 357Glossary 358Index 367