PY0547_Week 8_Sex & Sexuality

Page 1: Introduction

• Course: Sex & Sexuality

• Institution: Northumbria University, Newcastle

• Week: 8

• Module Code: PYO547 Psychobiology I

• Instructor: Dr. Fiona Dodd

Page 2: Pros and Cons of Sex

• Discussion of the reasons for engaging in sexual activity.

• Pros: 10 factors

• Cons: 3 factors

Page 3: Reasons for Sexual Activity

• Continuation of the species: Reproduction as a primary reason for sex.

  • Health and life risks associated with reproduction.

  • Many species can utilize asexual reproduction, raising questions about the necessity of sexual reproduction.

Page 4: Tinder and Reproductive Strategies

• Discussion on modern dating apps (e.g., Tinder).

• The joking proposition of cloning oneself instead of using dating platforms.

Page 5: Genetic Variation

• Benefits of sexual reproduction:

  • More gene combinations arise.

  • Enhanced resilience to diseases and parasites.

Page 6: Lecture Focus

• Topics of focus for the day:

  • The role of hormones and brain regions in sexual development and differentiation.

  • Understanding how sexual orientation is determined.

Page 7: Guidelines and Disclaimer

• Approach sensitive topics with care during discussions.

• Encourage respect in discussion boards and activities.

• Acknowledgement of outdated terms in literature, emphasizing respect for updated terminology (e.g., avoiding the term 'hermaphrodite').

Page 8: Definitions

• Sex: Defined as an individual’s biological sex determined by chromosomes (X and Y).

• Gender: Socio-cultural identity, distinct from biological sex, allowing for broader identification.

Page 9: Sexual Development Overview

• Introduction to the developmental aspects of sexual differentiation.

Page 10: Hormonal Functions in Development

• Differentiation between organizing and activating sex hormones and their roles in sexual behavior and maturation.

Page 11: Sexual Differentiation

• Overview of stages and processes in sexual differentiation.

Page 12: Genetic Basis of Sex

• Fertilization Process:

  • Egg (XX) + Sperm (XY) => Zygote.

Page 13: Role of the SRY Gene in Womb

• At 6 weeks gestation, SRY gene determines the development:

  • Produces Testis-Determining Factor (TDF).

  • TDF triggers male development; absence leads to female development.

Page 14: Development of Genital Structures

• Before 7 weeks: Genital structures appear similar.

  • Male: Wolffian ducts; Female: Mullerian ducts.

Page 15: The Complexity of Sex Development

• Infographic indicating the complexity of developing male and female characteristics at birth.

Page 16: Androgen Insensitivity Syndrome (AIS)

• Definition of AIS:

  • XY fetus with functioning SRY but ineffective androgen receptors (AR).

  • Develops testes, female internal organs degenerate, external female genitalia develop.

  • Individuals typically identify as women.

Page 17: Biological Sex Spectrum

• Explanation of various chromosomal combinations resulting in differences in biological sex spectra (e.g., XO, XXX, XXYY).

Page 18: Understanding Questions

• Check understanding questions regarding sex chromosome combinations and the SRY gene's chemical product.

Page 19: Reinforcement of Understanding Questions

• Reiteration of questions from Page 18 for assessment.

Page 20: AIS Definition Review

• Reiteration of criteria and understanding questions regarding AIS.

Page 21: Further Q&A on AIS

• Similar to previous pages, reinforcing understanding.

Page 22: Brain Differentiation by Sex

• Focus on how brains of different sexes show differentiation.

Page 23: Male vs. Female Brain Structures

• Brain structure differences that may influence behavior and cognition.

Page 24: Review of Literature

• Complexity of literature regarding brain gender: thousands of brains analyzed.

  • Findings suggest no strict dichotomy in brain structures.

Page 25: Gendered Brain Characteristics

• Observations of male and female brain size differences at birth.

  • Medial temporal cortex in males, DLPF in females being larger.

Page 26: Evaluating Literature

• Reasons for mixed literature results:

  • Variation in samples, ages, sociological factors, methodologies, and biases.

Page 27: The Brain as a Mosaic

• Diversity in Brain Structure:

  • Variability among individuals, revealing brain structures cannot be strictly categorized into male or female.

Page 28: Transgender Brain Studies

• Limited studies on transgender brains focusing on structural differences.

  • Findings indicate similarities to cisgender individuals of identical preferences rather than natal sex.

Page 29: Nature vs. Nurture in Sexual Orientation

• Discussion on the continuum of sexual orientation.

Page 30: Influences on Sexual Orientation

• Various factors influencing sexual orientation:

  • Genetics, early hormonal influences, environmental factors.

Page 31: Genetics of Male Sexuality

• Concordance rates in studies of male homosexuality regarding sibling relationships.

Page 32: Genetics of Female Sexuality

• Concordance rates in studies of female homosexuality.

Page 33: Nucleus Volume and Sexuality

• Investigative findings by LeVay (1991) showing brain structural differences between homosexual men and heterosexual individuals.

Page 34: Epigenetics and Sexual Orientation

• The impact of epigenetic modifications in twins with differing sexual orientations.

Page 35: Fraternal Birth Order Effect

• Increasing odds of homosexuality with each older brother due to maternal factors.

Page 36: Maternal Immune Hypothesis

• Understanding maternal immune responses to male fetuses and its implication on sexual orientation.

Page 37: Family Dynamics and Sexuality

• Studies indicating that family context might influence the likelihood of children exploring same-sex relationships.

Page 38: Family Structure Effects

• No strong impacts of family structure types on boys’ sexual partnerships, but some effects seen in girls regarding sexual debut age.

Page 39: Scholar's Perspective on Nature of Sexuality

• Emphasis on avoiding biological determinism or oversimplifications in understanding sexuality.

Page 40: Summary of Learnings

• Major points discussed:

  • Evolutionary perspective on sex.

  • Hormonal regulation in sexual development and differentiation.

  • The biological-environmental interaction in sexuality.

Page 41: Limitations and Critiques

• Acknowledge biases towards male homosexuality in current studies and lack of coverage for other sexual orientations and identities.

Page 42: Blackboard Activities

• Suggested activities for students: critique of LeVay (1991) study, watching a TED Talk on intersex issues.