The Biology of Sex

Lesson 1: The Biology of Sex

• Facts and values are often intertwined when discussing sex differences, causing confusion in debates.
• The chapter will focus on the biological aspects of sex differences.
• Students should learn about the biological differences between sexes and consider innate differences when studying gender.
• Biology demonstrates male and female similarities and developmental continuity.
• Males and females share a body plan, with anatomical differences being more apparent than real.
• The clitoris and penis are biological equivalents; men possess a vestigial womb which may cause prostate enlargement in old age.
• Sex can refer to the differences between males and females or to mating behavior that starts sexual reproduction.
• Biologically, 'sex' is the exchange and mixing of genetic material.
• Division into male and female in evolutionary terms allows greater variation and breeds out genetic weaknesses.
• Males determine a child's sex with a chromosome in their sperm
• Female ovary and male testis cells contain 23 chromosomes that carry coded genetic information.
• One of the 23 is a sex chromosome, with either X or Y type
• The Y chromosome looks like an incomplete X and is one-fifth the size.
• Female ova contain only the X sex-determining chromosome.
• Male sperm carries either the X or Y chromosome.
• XY sex determination results in a male embryo; XX results in a female embryo.
• Genetic or chromosomal sex is determined at conception.
• The differences in male and female anatomy result from nine months of gestation.
• Up to seven weeks prenatally, external genitalia looks the same in both sexes, and development plans for sex organs and ducts are common.
• There is a single external opening (urogenital opening) and a genital tubercle that becomes either the penis or clitoris.
• After seven weeks, male ducts stop developing in females and female ducts in males.
• A male embryo's genital tubercle enlarges to form the penis, and the urethra extends through it.
• The skin around the urogenital opening becomes the scrotum, where the testes later descend.
• In female embryos, the genital tubercle atrophies into the clitoris, and the skin around the urogenital opening becomes the labia.
• Embryos failing to develop fully as male or female are due to issues in the critical early period of differentiation.
• The method of the chromosomes' message being transmitted to the developing embryo and issues in imperfect sexual development remain unclear.
• The basic human form appears to be female adding something results in masculinity.
• Freemartins, intersexed calves born twin to a normal male where placentas are joined, starting as genetic females being masculinized by hormones.
• Hormones are produced in the male calf's testes and circulated to the freemartin.
• The Y chromosome provokes hormone production in the embryonic gonad, unlike the XX combination.
• The genes' influence on the Y chromosome is still unknown.
• Gonadal hormones start male development which has been shown in animal experiments.
• Male hormone injection into a female during the critical period can completely reverse its sex.
• Castrated embryos of either genetic sex develop into females
• Male hormone ensures the development of male structures and prevents the development of female structures
• For a female to develop, female hormones aren't needed, and normal sex differentiation needs the presence or absence of the male hormone alone.
• Studies of intersexuals provide evidence of hormonal importance in anatomical sex differentiation.
• An individual of one chromosomal sex develops gonads of the opposite sex, and those hormones create a physical appearance unrelated to chromosomal sex.
• One form of intersexuality is when genetic males have male gonads but female secondary sex characteristics and female external genitalia.
• It is thought this is due to the male gonad failing to produce male hormones during prenatal life.
• In rabbits, castration before embryonic day 21 results in complete female development of a genetic male
• Castration at day 24 doesn't interfere with normal male development.
• In humans, the critical period is a few days late in the third prenatal month, and after this time, hormones have no irreversible effect.
• Hormones are secretions of endocrine glands like the pituitary, adrenal glands, thyroid glands, pancreas, ovaries, and testes.
• Males and females make similar hormones with women have more estrogen and progesterone, and males have more testosterone and androgens
• Sex hormones are produced not only by the gonads but by the adrenal glands as well.
• This accounts for castrates ability to have a normal sex life and for cases of genital appearance differing from chromosomal sex.
• Tumors in the adrenal glands of adults can cause hormone reversals which change appearances in secondary sex characteristics.
• The body can manufacture male hormones from female and vice versa, complicating hormone measurement methods.
• An injection of testosterone (male hormone) can convert into estrogen (female hormone).
• Rapidly maturing male adolescents sometimes acquire small breasts, due to testosterone metabolizing as estrogen, which causes breast development.
• Up to about eight or ten years of age, boys and girls secrete negligible amounts of the sex hormones increasing thereafter in both sexes
• As puberty approaches, male hormone production in both sexes becomes pronounced.
• The increase peaks in the age range of twenty to forty, when hormone differences between men and women are at their highest.
• Increase in female hormone in girls is greater than boys, speeding up around age eleven
• Girls accelerate particularly around age eleven, and cyclically eighteen months before menstruation starts.
• Estrogen in boys and androgen in females doesn't become cyclic.
• Hormone amounts and proportions vary greatly, so it isn't possible to establish biological maleness or femaleness from hormone count.
• I n one study of two women and three men (all 'normal' individuals) the level of female hormones excreted in the urine was 155.2 and 13.4 units per day for the two women, and 12.4, 7.6 and 16.8 units for the three men.
• Male hormone production varies between individuals of the same and different sexes.
• It is possible to classify both men and women in nine categories by production of low, medium, or high levels of male and female hormones.
• Mixtures of sexes are found in each group, some might be male or female.
• The primary function of sex hormones is to develop the body inline with chromosomal sex so procreation can happen.
• Other sex hormone functions are directly involved in recreative behavior whereas others are obscure.
• Male hormones support body hair growth but don't support scalp hair growth.
• Females that get tested with testosterone for breast cancer tend to grow hair on their faces as well exhibit male patterned boldness.
• Males with estrogen tend to slow growth in hair on the face.
• In girls, rising estrogen production causes bone maturation that stops further growth.
• Because boys' estrogen levels are small, boys have longer time to grow before the bones mature.
• Sex hormone output might control growth hormone secretion from the pituitary gland. Omen monitors womb changes during menstruation, ovulation, conception, and gestation and keeps the vagina in a lubricated receptive state.
• Estrogen count in a person doesn't change the want for sex, sensations, or ability to orgasm.
• After menopause, estrogen production shrinks, but women can experience sexual arousal because worry for pregnancy is gone.
• At late fifties and early sixties both ovaries and testis start to produce smaller hormones and men and women go back to a neutral position.
• Genetic maleness correlates with penis, testicles, size, weight, and strength, the sum of Y chromosome advantages.
• Height/weight sex differences may be linked to food intake, males traditionally geting more food.
• During the Biafran war in 1970, the British observed that female children being commonly malnourished because males being given more food.
• One Margaret Mead tribe—the Mundugumor—had women as tall as males were they eat large amounts of foods before they provide food for the males.
• There are sex differences in somatotype, girls less often have muscular features.
• Genes on the X chromosome somehow limit building muscles.
• Body traits (trunk, head, limbs) varies by sex, with males and females diverging.
• Somatotype variation depends on ethnic group.
• In Manus of the Admiralty Islands there is no somatotype difference, and men and women have the mesomorph body type.
• In Bali, males/females share body look (Geoffrey Gorer called 'hermaphroditic' type), little height difference, similar shoulders/hips, babies can "suck their fathers' breasts"

Lesson 2: Sex, Gender and Families

• Sex and gender affect what is expected of someone and dating relationship behaviors, marriage partnerships, and parenting styles.
• The chapter introduces sex and gender concepts with macro and micro dimensions.
• Differences exist between sex and gender, including biology and social constructs.
• People learn about gender in many ways including family, media, race and class.
• Rigid gender expectations harm males and female.
• Margaret Mead and Adrienne Rich discuss sex, gender and families.
• Sex means reproductive biology.
• Sex categories aren't always visible like intersex individuals due to chromosonal problems.
• Some people disagree over what features constitute to be "intersex," surgical normalization happens around once in a thousand births.
• The genitals are altered to fit the XX/XY pair.
• Gender describes the meaning of masculine/female from a social level which entails attitudes and behaviors without involving biological features.
• Gender is created in the environment
• Both males and females are not viewed as the same in many societies
• In many societies throughout the world men are seen as more forceful, confident, rational and women are nurturing and dependable.
• Society reinforces the assumed ideas through parents by making mom be more nurturing than dad.
• The concept that men and women being opposites is wrong considering the researchers note there are more similarities than differences.
• Emotiveness, agency are all found in the other gender and people show similar feminine and masculine nature.
• Gender expectations depend on what social class you're in and reflect social patterns.
• What gender you express is not innate or natural and more from what environment you're in.
• Some have stronger bodies, tend to be loud, and are violent where as people who have female hormone levels tend to stay low due to the strength to raise children.
• Males have higher rates of death at a young age.
• Men can use intellectual skills better than the other gender (math) where as women's precision skills/ recall is higher.
• When some children act as men, their "brains" seem to change as they mature.
• Many cultures see genders act in opposite ways than you expect.
• Some people are seen as being more feminine or the other way around.
• Gender is instilled into you in the environment that you group up in.

Where Do We Learn Gender?

• If much of gendered behavior is socially constructed and learned, gender socialization teaches societal norms of male or female roles
• Gender socialization can be a teacher reprimanding a girl for rowdiness or a boy for emotional expression.
• It can occur at less conscious levels with parents picking different toys, and the agents of socialization summarized in Table 1.
• The agents of socialization, summarized in Table 1, include the people, social institutions, and organizations that teach boys and girls their gendered expectations.
• Parents and family members teach norms and expectations for wear, behavior, play, status or other expectations
• Without realizing family treat sons and daughters different, holding girls more gently or describe dainty features for girls.
• Children in childhood end up acting the way they were expected to with assignment of rules, toys, chores, etc.
• As men grow they choose to become leaders and want to do more.
• For families that have male sons they are more stable and don't expect divorce.
• Games and toys can encourage gender roles; girls dolls and men guns.
• Most stores set apart "pink toys" for girls or "blue toys" for boys.
• Toys as unisex as bikes can have a gender by being in pink or blue.
• For girls, dolls help learn skills.
• Toy dolls focus on reinforcing adult ideas.
• In some children's books males are seen more in the lead and girls less in illustrations, having many women with paid work.
• Colleges, preschool and lower/early level schools can teach gender, but today it is changing
• The girls do as good as can be women and tend to get degrees more easily.
• Education colleges stick with females and the engineering colleges are made up of males.
• In the US the females tend to excel when it comes to education.
• Same sex children tend to go together and boys tend to be violent.

DIFFERENCES BETWEEN THE SEXES ARE CULTURAL CREATIONS. Margaret Mead

• Source: Sam Atkinson (2015). The Sociology Book: Big Ideas Explained pp. 298-299 In early 20th-century US society, a man's role was to provide for his family, while women were relegated to the private sphere and considered responsible for childcare and housework because they were thought to be naturally more inclined to such roles.
• Margaret Mead, believed that gender is not based on biological differences between the sexes but cultural conditioning.
• Mead's investigations of the intimate lives of non-Western peoples in the 1930s and 1940s crystallized her criticisms claimed ways that gender and sexuality restricted possibilites for men and women.
• Mead says there can be punishments or accomplishments for society to accept what gender role you are showing, with a man being superior.
• Arapesh men women gentle, and women undertook childcare.
• Women as violent as men, Mundugumor behaved masculine way when it comes to the women act a same as powerful people.
• Certain masculine society regards acts coded as male where it's the opposite.
• Mead's theory was that the "society creates the role," not just the gender.

HETEROSEXUALITY MUST BE RECOGNIZED AND STUDIED AS AN INSTITUTION. Adrienne Rich

• Source: Sam Atkinson (2015). The Sociology Book: Big Ideas Explained pp.306-309. If women accept roles due to the views of women as inferior.
• Heterosexuality is the core/foundation but it needs challenging.
• The power causes for those relationships/binary where men is powerful over female that acts as something to base off when conducting something and express how men/women are.
• If someone doesn't live that lifestyle (heterosexual) you can behave deviant or dangerous. Some labels for being abnormal.

Lesson 3: Social Stratification, Social Class, and Families

• How does your social class position shape your family and intimate relationships? Social class is interwoven relationships that can make your lifestyle very different.
• Learning what social affects are to where your social class is involved such as family, and differeing views of why there is poverty.
• Exploring families along with how they are structured within social class.
• It is by a random act that can determine someones life by ethnicity, race, that determines what they can or can achieve such as jobs.
• In society social class has a big affect that has made it touch every part of others' lives.
• Life with rich people is vastly different considering the differences in families.
• In sex, race, or ethnicity, people are aware that the different social classes show effect on others lives.
• With people acting fame they get media attention (The rich and desperate of others situations).
• It's not just the money but everything that follows such as ways to go about their everyday life.
• Class dictates how access to living health and health benefits in the lowest class.
• They value authority and have obedience due to having no choice.
• Where as those of high class allow "problems" such as creativty, this makes the difference in how easy living and how hard it is on the mental process.
• Having less wealth is negative on the value of home with some situations becoming a problem (abuse or negligence).
• Attending college will also matter for people of lower class may know little to no people can change to go to college and say it's not a worth investment therefore not doing so.
• Being poor will come with consequences/stresses such as finances, this can be very difficult to deal with.
• Recognizing the difference between the classes will help with a range of social economical problems.
• In other people live great have a wealth life it can be seen that people look at it as somewhat the same.
• People are born into wealth where is people who gain it through hard labor.
• For the caste system the ranking system can have problems where they have no freedom the social standing with having the freedom to change it up.