Chapter 2 Biology, Sex, and Gender The Interaction of Nature and Environment

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 The Sex Chromosomes and Sexual Differentiation Sex chromosomes Typically, a person has 46 chromosomes arranged in pairs –One pair is the sex chromosomes Males are XY Females are XX –This differentiation begins in the sixth week after conception. –Until then, the fetus is sexually bipotential

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 The Case for His and Hers Brains The brain is divided into two halves or hemispheres Brain lateralization Empathizing-systemizing (or E-S) theory Are sex differences in the brain present at birth, the products of innate biology?

Chromosomes and Sexual Characteristics There are multiple types of chromosomal errors. –Turner Syndrome.. No Y chromosome so no male genitals –XYY.. Impact on appearance and aggressiveness ? –Assorted hormonal impacts on chromosomal development These can produce genital ambiguity Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

The Sex Chromosomes and Sexual Differentiation –Prenatal Hormones and Gender –Congenital adrenal hyperplasia (CAH) –Androgen insensitivity syndrome (or AIS) –DHT deficiency syndrome –Guevedoces

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 The Sex Chromosomes and Sexual Differentiation Androgens: Male Hormone Testosterone –Female Hormone Estrogen Mu ̈ llerian inhibiting substance (MIS) Inhibits female ducts Dihydrotestosterone (DHT) Prompts development of external genetailia Chromosomes and Gender

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 The Sex Chromosomes and Sexual Differentiation Genital Ambiguity: What Can It Teach Us about Gender? –The development of a masculine or feminine gender identity is quite independent of either: A pair of XY or XX sex chromosomes or the production of particular hormones

The Hormone Puzzle Chromosomal basis –XX = female; XY = male –X has greater genetic background Aggression –Animal vs. human studies –Physical vs. relational aggression Maternal instinct –Parent-child bonding Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

“My Hormones Made Me Do It” Testosterone and Gender –Research on aggression yielded consistent findings of sex differences in behavior: From preschoolers to adults –Findings do indicate that high levels of circulating testosterone are correlated with: Edginess, competitiveness, and anger

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 Figure 2.1 External Genital Differentiation in the Human Fetus

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 Figure 2.1 External Genital Differentiation in the Human Fetus

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 Figure 2.2 Normal Male Meiosis and Nondisjunction of Sex Chromosome

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 Figure 2.2 Normal Male Meiosis and Nondisjunction of Sex Chromosome

Ambiguous Sex and Gender Identity Intersexed infants (hermaphrodites) –Violate the principle of Sexual dimorphism –Gender identity and the timing of sex reassignment surgery Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Ambiguous Sex and Gender Identity, cont. Transsexuals –Incongruity of biological sex and gender identity –Current studies show more satisfaction with sex reassignment surgery than in the past –Discussion: A Case Study: A Sex Reassignment Tragedy Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Chromosomes and Sexual Characteristics Genital ambiguity has led to some doctors to “surgically correct” children born in this condition John Money has been a leader in transgender studies and procedures. Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Alternative Sexual Definitions Anne Fausto-Sterling,Professor of Biology and Women's Studies in the Department of Molecular and Cell Biology and Biochemistry at Brown University has argued that two sexes are not enough.two sexes are not enough. Example: Caster Semenya, the eighteen-year-old South African runner who set the world's fastest time of 1:56.72 in the women's 800 metres race at the World Athletics Championships in 2009, made for headline news long after the race was won. It was not speed, however, that had everyone talking about Caster, but rather the question: Is she a boy or a girl? Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Alternative Sexual Definitions Anne Fausto-Sterling,Professor of Biology and Women's Studies in the Department of Molecular and Cell Biology and Biochemistry at Brown University has argued that two sexes are not enough. She maintains that sex is best understood not as a dichotomy, but as a continuum, meaning that there are more than two sexes. She writes, "While male and female stand on the extreme ends of a biological continuum, there are many bodies.... that evidently mix together anatomical components conventionally attributed to either males or females."two sexes are not enough. Example: Caster Semenya, the eighteen-year-old South African runner who set the world's fastest time of 1:56.72 in the women's 800 metres race at the World Athletics Championships in 2009, made for headline news long after the race was won. It was not speed, however, that had everyone talking about Caster, but rather the question: Is she a boy or a girl? The standard medical term for such people is intersex. This is a catchall term for multiple configurations of human anatomy. Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Alternative Sexual Definitions According to Fausto-Sterling there are three major subgroups with some mixture of male and female characteristics: the so-called true hermaphrodites. –herms, who possess one testis and one ovary (the sperm- and egg-producing vessels, or gonads) –Male pseudohermaphrodites (the "merms"), who have testes and some aspects of the female genitalia but no ovaries –Female pseudohermaphrodites (the "ferms"), who have ovaries and some aspects of the male genitalia but lack testes. Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Alternative Sexual Definitions The psychologist John Money of Johns Hopkins University, a specialist in the study of congenital sexual-organ defects, suggests intersexuals may constitute as many as 4 percent of births. Almost at once such infants are entered into a program of hormonal and surgical management so that they can slip quietly into society as "normal" heterosexual males or females. Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Alternative Sexual Definitions Going beyond biological origins there are other categories to be aware of Transgender- people dress across sexual expectations, aka cross dressing. Transsexual –people who get medical treatments to change their physical sexual characteristics Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Alternative Sexual Definitions Going beyond biological origins there are other categories to be aware of Transgender- people dress across sexual expectations, aka cross dressing. Transsexual –people who get medical treatments to change their physical sexual characteristics Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Evolution, Genetics, and Biology Sociobiology –Biological roots of social behavior –Critique: Androcentric, Deterministic Cognitive Biology –Prenatal hormones effects on brain development –Spatial ability for males, verbal ability for females –Critique: Women and men are more alike than different Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 The Case for His and Hers Brains The notion that men and women have different brains is an old one Much of the research uses the brains of animals, usually rats, not humans Biology and Sexual Orientation Neuroplasticity

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 Figure 2.3 The Human Brain

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 The Interaction of Biology and Culture Feminist critiques of biological theories of gender have tended to conceptualize: –Biology as something that comes first Birke urges feminist scientists to move beyond critiques that simply: –Replace biological determinism with social constructionism that denies the body

Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson 2012 The Interaction of Biology and Culture Transformative account of gender development –Examines how culture & individual behavior impact biology & physiology, and vice versa Underlines the pitfalls of using biological principles to justify gender inequality

Conclusion To summarize –Sex is biological and physical –Gender is social and in people’s minds –We are going to examine how society constructs gender How society regulates and controls both gender and sexual activity. If you are interested in the topic of alternative sexual characteristics I suggest you read two sexes are not enoughtwo sexes are not enough Portions Copyright by Alan A. Berger, 2012 and other portions copyright by Pearson