How does biology make us male or female

Chapter 10

Sex, gender, and sexuality

Jo-Anne D. Petrie, M.Ed. Psychology 260 Fall 2018


Big Questions How does biology make us male or female? Why do we act masculine or feminine? How do we vary in sexual orientation? What motivates us to have sexual relations (or not to)?

How does biology make us male or female?

Biological sex refers to physical factors that determine the sex of a person

Sex chromosomes-xx Female/ xy male

Sex glands-ovaries (F) release more estrogen and develop mature eggs

Males testes (M) release more androgens (testosterone) and develop mature sperm cells.


Biological sex

Refers to physical factors that determine one’s sex as male or female

NOT the same as gender

Social differences between being male or female

Humans are more than just male or female

Gender nonconformity

Some people don’t feel especially male or female

Some may feel more male in some situations and more female in other situations (i.e., gender nonconformity)

Secondary Sex characteristics


increased release of estradiol

defining in the waist

increase in fat

breast development

body hair (arm pits)

pubic hair


Secondary Sex characteristics


Greater muscle mass

Facial hair

Deepening voice

Angular jaw

Body hair (armpits and chest)

Pubic hair









Primary Sex Characteristics


Mature internal organs (uterus and ovaries with egg cells)

Mature genitals (vagina)

Menarche- woman’s first menstrual period



Mature internal organs (testes with sperm cells)

Mature genitals (penis)

Spermarche -is the beginning of development of sperm in boys’ testicles at puberty.




Less reactive amygdala –(a roughly almond-shaped mass of gray matter inside each cerebral hemisphere, involved with the experiencing of emotions) – larger and more reactive orbito-frontal cortex create a tendency toward less physical aggression


More reactive amygdala smaller obrito-frontal cortex and reduced coupling of amygdala and prefrontal cortex create a tendency toward physical aggression.


Biological sex

Sex chromosomes

Genetic material determined at conception by the 23rd pair of chromosomes in fertilized egg

Mother’s egg cell always donates X chromosome

Father’s sperm cell either donates X or Y chromosome

Female XX sex chromosomes

Male XY sex chromosomes

Sex determined by whether a sperm that fertilizes egg carries X or Y chromosome

What happens as in the case of Coy Mathis?

Gender is not the same as biological sex.


What happens when children’s genitals are not fully developed and their parents decide the sex for them?

Hormonal abnormalities 1 in every 1,500 children are born with no clarity of either a vagina or penis

Reason being maybe exposed to androgens in utero.

Androgen Insensitivity Syndrome (AIS)

-body doesn’t respond to testosterone  -not fully developed penis, testes don’t descend -may have what looks like a vagina


Let’s discuss what can happen in this case?







chromosomes and hormones


environnent, parents/peers/society/media influences



XXY Klinefelter Syndrome

Boys born with 3 chromosomes

Symptoms: Birth-small testes and penis, misplaced/delayed speech

Puberty-don’t have normal development of secondary sex characteristics, develops some fat on breasts




Turner Syndrome

Girls missing a chromosome Symptoms: Birth- no abnormalities externally Puberty- lack of 2nd sex characteristics, shorter, never menstruate due to undeveloped ovaries


ancy or in early childhood. Occasionally, in females with mild signs and symptoms of Turner syndrome, the diagnosis is delayed until the teen or young adult year




Physical doesn’t match chromosomal makeup


Variety of conditions in which a person is born with a reproductive or sexual anatomy that doesn’t seem to fit the typical definitions of female or male.

For example, a person might be born appearing to be female on the outside, but having mostly male-typical anatomy on the inside.

Or a person may be born with genitals that seem to be in-between the usual male and female types—for example, a girl may be born with a noticeably large clitoris, or lacking a vaginal opening, or a boy may be born with a notably small penis, or with a scrotum that is divided so that it has formed more like labia.

Or a person may be born with mosaic genetics, so that some of her cells have XX chromosomes and some of them have XY.



Social, cultural, psychological aspects of masculinity and femininity

How has what we explored thus far or your knowledge differ from the stereotypical “gender” stereotypes?


Gender Schemas

cognitive model about being male/female and masculine/feminine


Gender Stereotypes

commonly held beliefs about what males/females are like and what they do


Gender Roles

position/characteristic/interest expected based on gender


Gender Identity

How you identify in terms of male or female regardless of anything else




Gender identity differs from biological sex





gender identity differs from biological sex



gender identity differs from biological sex


Gender Dysphoria

Experiencing depression/ stress/ anxiety related to being transgender, go one for 6+ months, interferes with day to day function


Sexual Orientation

Has to deal with who you are attracted to sexually/romantically/emotionally




Attracted to other sex



Attracted to same sex



attracted to all sexes



attracted to neither men or women







Discovery/Research Therapy Coming Out Hormones Passing Name Change Surgery

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