Module 5, Emotion & Behavior: 10.3 Sexual Behavior, Sexuality, and Gender Identity

Learning Objectives

  • By the end of this section, students will be able to:

    • Understand basic biological mechanisms regulating sexual behavior and motivation

    • Appreciate the importance of Alfred Kinsey’s research on human sexuality

    • Recognize the contributions that William Masters and Virginia Johnson’s research made to our understanding of the sexual response cycle

    • Define sexual orientation and gender identity

Importance of Sexual Behavior

  • Sexual behavior is as essential to human life as food.

  • From an evolutionary viewpoint, sex is critical for species perpetuation.

  • However, sexual behavior encompasses more than just reproduction.

  • This section will overview research on human sexual behavior and motivation, concluding with discussions on gender identity, expression, and sexual orientation.

Physiological Mechanisms of Sexual Behavior and Motivation

  • Much of the current understanding of sexual behavior and motivation stems from animal research.

  • The hypothalamus plays a significant role in motivated behaviors, including sexual behavior.

    • Lesions in the medial preoptic area disrupt a male rat's capacity for sexual behavior.

    • Medial preoptic lesions do not affect how much work a male rat is willing to perform to gain access to a receptive female.

    • This suggests that sexual engagement ability and sexual motivation may be governed by different neural systems.

  • Research indicates that limbic system structures such as the amygdala and nucleus accumbens are critical for sexual motivation.

    • Damage to these areas reduces motivation for sexual behavior, but the ability to engage in sexual activity remains intact.

    • Similar findings have been observed in female rats.

Implications for Human Sexual Behavior

  • Some parallels exist between animal and human sexual behaviors.

  • The popularity of medications for erectile dysfunction illustrates this dissociation in humans between sexual motivation and engagement.

  • Disorders linked to abnormal hypothalamic function often lead to conditions such as hypogonadism (reduced gonadal function) and diminished sexual functioning.

  • Hormones from the endocrine system critically influence sexual motivation.

    • Examples: Many animals show no sexual motivation without the appropriate sex hormones from their gonads.

    • In humans, sexual motivation varies with circulating testosterone levels across all genders.

Kinsey’s Research

  • Prior to the late 1940s, reliable empirical data on sexuality was scarce.

    • Physicians held authority on sex-related issues but had little training.

  • Alfred Kinsey, from Indiana University, initiated large-scale survey research on human sexuality (e.g., Sexual Behavior in the Human Male in 1948 and Sexual Behavior in the Human Female in 1953).

  • These reports marked a significant shift as private sexual behaviors underwent scientific scrutiny.

  • Kinsey's findings included:

    • Women show equal interest and experience in sex as men.

    • Both genders engage in masturbation without adverse health outcomes.

    • Same-sex or same-gender sexual relationships and acts are prevalent.

  • Kinsey introduced the Kinsey scale, a continuum to categorize sexual orientation.

Masters and Johnson’s Research

  • In 1966, William Masters and Virginia Johnson published findings from their extensive observation of sexual behavior.

    • They directly recorded physiological responses during sexual acts—nearly 10,000 acts observed.

    • Key physiological measurements recorded included blood pressure, respiration rate, vaginal lubrication, and penile tumescence.

  • They delineated the sexual response cycle into four phases:

    • Excitement Phase: Marked by penile erection or clitoral swelling and vaginal lubrication.

    • Plateau Phase: Further swelling of the vagina, increased blood flow to the labia minora, and full erection of the penis.

    • Orgasm Phase: Rhythmic contractions in females involving the pelvis and uterus, and ejaculation in males characterized by pelvic contractions.

    • Resolution Phase: Rapid return to an unaroused state with decreased blood pressure.

  • The refractory period follows orgasm, affecting the ability to achieve further orgasms, varying in duration by individual factors such as age.

  • Masters and Johnson’s work has also contributed statistics regarding average penis sizes and the elasticity of the vagina.

Sexual Orientation

  • Sexual orientation is defined as an individual's emotional, romantic, and/or erotic attraction to others.

  • Sexual orientations include:

    • Lesbian: Women attracted to women

    • Gay: Men attracted to men

    • Bisexual: Attraction to own and other genders

    • Pansexual: Attraction without regard to sex or gender

    • Asexual: Little to no interest in sexual activity

    • Heterosexual (Straight): Attraction to different genders

  • Distinction exists between sexual and romantic orientations; e.g., aromantic individuals do not feel romantic attraction.

  • Many orientations exist on a spectrum, illustrating the fluidity of individual experiences.

  • Abbreviations reflect identities like LGBTQ (lesbian, gay, bisexual, transgender, queer/questioning) and may include variants for intersex and asexual individuals, as well as a plus sign for other identities.

Understanding Sexual Orientation

  • Prior perspectives suggested that sexual orientation was determined predominantly by socialization, but genetic and biological evidence presents a strong argument for innate biological components influencing orientation.

  • Research supports gene-level contributions to sexual orientation, suggesting that genetic factors account for at least half the variability seen in sexual orientation.

  • Significant differences in brain structure and body function have also been observed among different sexual orientations.

  • Sexual orientation is not considered a choice and represents a relatively stable characteristic.

  • Conversion therapy—claims regarding changing orientation—has prompted substantial critique within the scientific community, and has been widely discredited.

  • Dr. Spitzer, known for supporting conversion therapy, later apologized for endorsing this approach and acknowledged its ineffectiveness.

Gender Identity

  • Gender identity is separate from sexual orientation; it pertains to an individual's internal understanding of their gender.

  • Transgender individuals experience a gender identity that differs from their assigned sex at birth.

  • Gender dysphoria describes the distress some individuals may experience when their gender identity does not align with their biological sex as classified at birth.

    • DSM-5 diagnostic category requires persistent dysphoria for at least six months and corresponding distress.

  • Transitioning may occur socially, legally, or medically to align one’s life with their gender identity. This may include:

    • Social Transition: Changes in presentation, name, pronouns, etc.

    • Legal Transition: Changing gender markers and names in legal documents.

    • Medical Transition: Using medical procedures to alter physical attributes.

  • Not all transgender individuals undergo medical or physical transitions; cross-dressing is not inherently linked to gender identity.

  • Intersex refers to individuals with variations in reproductive or sexual anatomies that don't fit typical definitions of male or female.

Cultural Factors in Sexual Orientation and Gender Identity

  • Cultural contexts significantly impact the understanding of sexual orientation and gender identities.

  • The United States is largely considered a heteronormative and cisnormative culture, creating specific societal expectations.

  • Some societies recognize more than two genders, where additional gender identities exist and may even be integrated into the society. For example, the Bugis people of Indonesia acknowledge five genders within their cultural framework.

  • Dr. John Money developed the theory of psychosexual neutrality, claiming socialization significantly impacts gender identity.

    • His experiment with David Reimer—birth name Bruce—failed to account for the biological aspects of gender identity and ultimately resulted in a tragic outcome that has influenced current understandings of gender and intersex conditions.

Conclusion

  • The discussion of gender identity and sexual orientation continues to evolve with ongoing research and societal changes. New understandings about gender as a spectrum and reduced stigma contribute to a more nuanced view of human sexuality and identity.