Comprehensive Guide to Sexual Differentiation, Gender Identity, and Sexual Orientation Study Guide

What is the biological definition of sex?

Determined by gamete size; individuals producing large gametes (eggs) are female, and those producing small gametes (sperm) are male.

How does the APA define sex?

Refers to a person's biological status, typically categorized as male, female, or intersex, indicated by sex chromosomes, gonads, internal reproductive organs, and external genitalia.

What does gender encompass?

Psychological, cultural, and social characteristics ascribed to men and women.

What is gender-normative behavior?

Behavior compatible with cultural expectations.

What is gender non-conformity?

Behavior viewed as incompatible with cultural expectations.

What is gender identity?

One's core sense of being male, female, both, or neither.

What are chromosomes?

Long, tightly packed DNA sequences; humans typically have 23 pairs (46 total) in most cells.

What determines the sex of a child?

The father's genetic contribution; he can provide either an X or a Y chromosome.

What is the difference between X and Y chromosomes?

X chromosome is larger (900-1400 genes), while Y chromosome is smaller (70-400 genes) and contains genes involved in male sexual differentiation.

What is the role of the SRY gene?

Located on the Y chromosome, it triggers differentiation in the male direction during embryonic development.

What happens in XX embryos in the absence of the SRY gene?

Development proceeds in the female direction.

What do both XX and XY embryos have at the undifferentiated stage?

A pair of undifferentiated gonads and two sets of ducts: Müllerian ducts and Wolffian ducts.

What develops from the Müllerian ducts in female-typical development?

Fallopian tubes, uterus, and upper part of the vagina.

What develops from the Wolffian ducts in male-typical development?

Vas deferens, seminal vesicle, and epididymis.

What is the effect of anti-Müllerian hormone (AMH) in males?

It causes Müllerian ducts to degenerate.

What are the characteristics of Turner Syndrome?

Genotype XO, usually infertile, short stature, broad chest, webbed neck, and widely spaced nipples.

What is Klinefelter Syndrome?

Genotype typically XXY, usually sterile, with delayed or absent puberty and low testosterone levels.

What is Triple X Syndrome?

Genotype XXX, usually fertile, may be taller than average, and may have learning disabilities.

What is XYY Syndrome?

Genotype XYY, typical male sexual development, but may have lower IQ and autism-related symptoms.

What is Ovotesticular Disorder?

Extremely rare condition where individuals have both ovarian and testicular tissue.

What causes Congenital Adrenal Hyperplasia (CAH)?

Gene mutation that impairs steroid metabolism, leading to excessive secretion of androgens.

What is Androgen Insensitivity Syndrome (AIS)?

Genotype XY; body cannot respond to testosterone, resulting in absence of internal reproductive tracts and typically female external genitalia.

What are the organizational effects of hormones during critical periods?

They cause permanent changes in sexual development, including brain organization.

What are activational effects of hormones?

Hormones trigger reversible behavioral responses related to reproduction in adulthood.

How does the hypothalamus differ between males and females?

The female hypothalamus directs cyclic secretion of sex hormones, while the male hypothalamus directs constant production.

What are some sex differences in brain structures?

Approximately 10 brain regions are larger in women and about 14 in men, affecting organization and neurotransmitter metabolism.

What is 5-Alpha Reductase Deficiency?

A rare deficiency of the enzyme 5-alpha reductase that converts testosterone to dihydrotestosterone, affecting genital development.

What occurs in utero for fetuses with XY genotype and 5-Alpha Reductase Deficiency?

They are exposed to testosterone, leading to internal male genitalia differentiation, but develop external female genitalia at birth due to lack of DHT.

What changes occur at puberty for individuals with 5-Alpha Reductase Deficiency?

Increased testosterone leads to muscle mass growth, penis and scrotum growth, descent of testes, voice deepening, and sperm production.

What is the definition of transgender?

Individuals who identify with a gender different from their assigned gender at birth.

What is gender dysphoria?

A DSM-5 diagnostic term for individuals experiencing distress due to the incongruence between their experienced/expressed gender and assigned gender.

What was the focus of DSM-III (1980) regarding gender identity?

It introduced 'Transexualism' and 'Gender Identity Disorder of Childhood' focusing on discomfort with assigned sex.

What significant change did DSM-5 (2013) make regarding gender identity?

It defined 'Gender Dysphoria' as significant distress or impairment from a mismatch between experienced gender and assigned sex.

What are the criteria for diagnosing gender dysphoria in children according to DSM-5?

Manifested by strong desire to be an alternative gender, wearing alternative gender-typical clothing, and preference for cross-sex roles.

What is the most likely outcome for childhood gender dysphoria?

Most children do not remain gender dysphoric after puberty; those who persist often have extreme characteristics.

What is sexual orientation?

Sexual attraction toward persons of the opposite sex (heterosexual), same sex (homosexual), both sexes (bisexual), or neither sex (asexual).

What does the Kinsey Scale measure?

It measures sexual orientation on a continuum from exclusively heterosexual to exclusively homosexual.

What did DSM-I (1952) classify homosexuality as?

A 'sociopathic personality disturbance.'

What did Evelyn Hooker's research suggest about homosexuality?

Her research found no significant differences between homosexual and heterosexual men, suggesting homosexuality is not a mental disorder.

What is the maternal immune hypothesis regarding sexual orientation?

It suggests that with successive male births, mothers may develop an immune response affecting fetal brain development.

What does the 2D:4D ratio indicate?

It reflects prenatal androgen exposure; a lower ratio indicates a typical male pattern, while a higher ratio indicates a typical female pattern.

What is the prevalence rate of Male-to-Female (MTF) transgender individuals?

Approximately 1 in 10,000 to 1 in 100,000.

What is the prevalence rate of Female-to-Male (FTM) transgender individuals?

Approximately 1 in 30,000 to 1 in 400,000.

What is the significance of the term 'cisgender'?

It refers to individuals who identify with their assigned gender at birth.

What is a demisexual orientation?

Sexual attraction only experienced after a strong emotional connection with someone.

What does the term 'queer' refer to?

Often a non-specific term referring to not primarily heterosexual.

What is the DSM-IV (1994) definition of Gender Identity Disorder?

It included strong, persistent cross-gender identification and significant distress or impairment.

What is the significance of the term 'asexual'?

A sexual orientation involving a lack of sexual attraction to others, though some may still desire intimacy.

What is the historical significance of Kinsey's research?

It argued for a continuum of sexual behavior, challenging the notion of discrete sexual orientation categories.

What is the typical age range for the first experience of gender dysphoria in children?

Between ages 3-7 years.

What is the controversy surrounding the rise in transgender identity?

Debates exist regarding explanations for the reversal of sex ratios and the increase in adolescents, as well as concerns about accurate diagnoses.

Sex

Determined by gamete size; eggs v. sperm.

APA Sex

Biological status typically as male, female, or intersex based on internal/external genitalia, gonads, reproductive organs.

Gender Normative

Behavior compatible with social/cultural norms.

Gender Non-Conformative

Behavior incompatible with social norms.

X-Chromosome

Chromosome larger than the Y chromosome containing 900-1400 genes; XX indicates female.

Y-Chromosome

Chromosome smaller than the X chromosome containing 70-400 genes, typically associated with male sexual differentiation.

Critical Period

Time window during which the presence or absence of testosterone (T) acts on the brain to masculinize or demasculinize it.

Development of Internal and External Organs

The precursor structures for internal and external genitalia: Gonads, Mullerian Ducts, Wolffian Ducts, genital tubercle, genital swelling, and genital folding.

XX Sexual Differentiation Pathway

In XX individuals, gonads develop into ovaries, Wolffian ducts degenerate, Mullerian ducts become fallopian tubes, uterus, and upper vagina, genital swelling becomes outer labia, genital folding becomes inner labia, and genital tubercle becomes clitoris.

XY Sexual Differentiation Pathway

In XY individuals, SRY gene leads to testis production, Wolffian ducts become vas deferens, seminal vesicle, and epididymis, AMH Gene causes degeneration of mullerian ducts, genital tubercle becomes glans penis, genital swelling becomes scrotum, and genital folding becomes shaft of penis.

SRY GENE

Gene responsible for the production of testis determining factor, leading to the development of gonads into testes.

AMH Gene

Gene responsible for the degeneration of mullerian ducts during male internal genital development.

Organizational effects

Hormonal effects that cause permanent changes.

Activational Effects

Hormonal effects that result in reversible changes.

Turner Syndrome

XO chromosomal condition (1/5000 conception, 1/3000 live births) characterized by webbed neck, wide spaced nipples, broad chest, short stature, spatial learning disabilities, and infertility with no functional ovaries.

Klinefelter Syndrome

XXY or XXXY chromosomal condition (1/600 live births) characterized by sterility, delayed puberty, low testosterone, small testicles, and a body masculinized by the Y chromosome but sometimes with a feminized appearance.

XYY Syndrome

XYY chromosomal condition (1/1000 live births) where individuals are typical males, tall, fertile with low sperm count, low IQ, and common autism-related symptoms.

Triple X Syndrome

XXX chromosomal condition (1/1000 live births) where individuals are usually fertile, taller than average, with wide set eyes, dental problems, and potential learning disabilities such as delayed speech or lower IQ.

Ovotesticular Disorder

An extremely rare intersex condition featuring both ovarian and testicular tissue, variable genital appearance, and typical infertility.

Congenital Adrenal Hyperplasia (CAH)

Intersex condition (1/13000) of impaired steroid metabolism where adrenal glands secrete low amounts of salt/water controlling steroids and high levels of testosterone, causing partial genital masculinization in XX individuals.

Androgen Insensitivity Syndrome

X-linked recessive condition (1/13000) in XY individuals resulting in malfunctioning testosterone receptors, causing a lack of male or female internal reproductive tracts, shallow vagina, internal testes, normal vulva, and feminine body/breasts at puberty.

5-Alpha Reductase Deficiency

Condition in XY individuals due to deficiency of the enzyme 5-alpha reductase (which converts T to dihydrotestosterone), causing internal male genitalia and external female genitalia until puberty, when increased testosterone causes masculinization.

Transgender

Identifying with a gender different from one's assigned gender.

Cisgender

Identifying with one's assigned gender.

Gender Dysphoria

Experience of significant distress resulting from a mismatch between one's desired/experienced gender and the gender assigned at birth.

History of DSM Criteria for Gender Identity Disorders

Historical progression of criteria: DSM III (1980) Transexualism and Gender Identity Disorder of Childhood, DSM IV (1994) Gender Identity Disorder, and DSM 5 (2013) Gender Dysphoria.

Transexualism (DSM III)

1980 DSM III diagnosis defined as discomfort with one's assigned sex in a post-pubertal person lasting at least 2 years, along with acquiring sex characteristics of the other sex.

Gender Identity Disorder of Childhood

1980 DSM III diagnosis defined by persistent cross-gender identification for at least 2 years, fantasy play in boys, and preference for masculine activities in girls.

Sexual Orientation

Sexual attraction.

Heterosexual

Primarily attracted to the opposite sex.

Homosexual

Attracted to the same sex.

Bisexual

Attracted to both sexes equally.

Pansexual

Attracted to people regardless of sex and gender.

Queer

Not primarily heterosexual.

Demisexual

Sexual attraction that develops only after a strong emotional connection is formed.

Asexual

Sexual orientation that lacks sexual attraction to others.

Evelyn Hooker (1957)

Researcher who conducted tests comparing gay and straight men, demonstrating no difference between the two groups and concluding homosexuality is not a mental disorder.

Maternal Immune Hypothesis

Hypothesis stating that progressive immunization to male-specific antigens following the birth of successive sons alters fetus male brain differentiation, increasing the likelihood of homosexuality by 33% per older brother.

Frotteuristic Disorder

Sexual arousal from touching a non-consensual person, most common in crowded public places.

Sexual Sadism Disorder

Sexual arousal from the suffering of another person, requiring presence for greater than 6 months.

Sexual Masochism Disorder

Sexual arousal from receiving pain.

Autoerotic Asphyxia

Oxygen deprivation achieved by means of neck compression during sexual activity.

Consensual Non-Consent

A set of practices in which a submissive partner agrees to a sexual situation where their ability to non-consent is limited.

Transvestic Disorder

Intense sexual arousal from fantasizing about dressing as another gender.

Autogynephillia

Becoming sexually aroused by imagining oneself as a woman.

Fetishistic Disorder

Sexual arousal derived from nonliving objects or non-genital body parts.