Gay, Straight, and the Reason Why
The Science of Sexual Orientation
Table of Contents
Chapter 1: What Is Sexual Orientation?
Criteria for sexual orientation
Sexual orientation in men and women
Stability of sexual orientation
Prevalence of different orientations
Are there categories?
Sexual orientation across cultures
Chapter 2: Why We Need Biology
Learning theories-influence of early sexual experiences
Learning theories-gender learning
Is it a choice?
The biological alternative
Chapter 3: The Outline of a Theory
Male and female brains
Male and female behaviors
Development of sex differences in animals
Sexual partner preference in animals
Origins of variation within each sex
Relevance to human sexual orientation
Sexual orientation in nature
Chapter 4: Childhood
Development of gendered childhood traits
Childhood traits associated with adult sexual orientation: retrospective studies
Chapter 5: Characteristics of gay and straight adults
Gendered traits in adulthood
Origin of gendered traits
Sexual orientation and cognitive traits: visuospatial abilities
Personality traits: Masculinity-femininity
Other personality traits
Chapter 6: The role of sex hormones
Hormone levels in gay and straight adults
Why focus on prenatal sex hormones?
Hormone levels during development
Congenital adrenal hyperplasia
Finger length studies
The inner ear
Central auditory system
Action of sex hormones on the developing brain
Possible causes of variability in prenatal androgen levels
Chapter 7: The role of genes
Is the family clustering caused by genes?
Molecular genetics-candidate-gene studies
Genes and sexuality in fruit flies
Genes, homosexuality, and evolution
The "fertile female" hypothesis
Beneficial effects on same-sex relatives
Chapter 8: The brain
A brief tour of the brain
The hypothalamus and sexual orientation
Other brain regions
Inhibition and sexual orientation
Chapter 9: The body
Body size and shape
Trunk and limb length
Sturcture of the face
Hair whorl direction
Chapter 10: The older-brother effect
How well established is the older-brother effect?
How strong is the older-brother effect?
The older-brother effect and handedness
What causes the older-brother effect?
Chapter 11: Beyond gay and straight
Bisexuality in men
Bisexuality in women
Age preference and pedophilia
Butch-femme and top-bottom
Chapter 12: Conclusions
Sexual orientation is linked to other gendered traits
A common origin for gender-shifted traits?
The role of genes
Does the older-brother effect work through prenatal hormones?
Is there a random biological influence?
How does sexual orientation become categorical?
Unconscious processes in sexual attraction and arousal
Changes in the prevalence and nature of homosexuality
What is sexual orientation?
Sexual orientation and gender: the social fallout