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Chapter 2 : Biology and Sex
Transcript of Chapter 2 : Biology and Sex
Biological Explanations of Sex
We've all heard these statements before, "Boys will be boys" and "It's her time of the month".
"There's also a certain conceptual tidiness to biological explanations, because the social arrangements between women and men (gender inequality) seem to stem directly and inevitably from the differences between us. Biological arguments reassure us that what
is what should be, that the social is natural.....We cannot be held responsible for the way we act - hey, it's biological!" (Kimmel, pg. 22, 2013).
"Men are the protectors and maintainers of women....Hence good women are devoutly obedient...As for those whose rebelliousness you fear, admonish them, banish them from your bed, and scourge them" (Qur'an, W. Kaufman, 1976).
"A man...is the image and glory of God; but woman is the glory of man. For man was not made from woman, but woman from man. Neither was man created for woman, but woman for man" (1 Corinthians 11:7-9)
"Wives, be subject to your husbands, as to the Lord. For the husband is the head of the wife as Christ is the head of the church....As the church is subject to Christ, so let wives also be subject in everything to their husbands" (Ephesians 5:22-24)
Religion & Politics
In the United States, the first female House Representative was elected in 1917.
Isabel Peron was the first woman in the world to become the President of a country (Argentina)
The Nineteenth Amendment (1920) :
gave women the federal right to vote.
24% of State Legislators are women and 12% are State Governors (6 states)
In the whole world, women hold only 20% of governmental seats.
In one survey, 94% believed God was male. Only 6% reported they thought God was female.
Very few, if any, organized religions place power in female hands. Many New Age Wiccans are the closest to worshiping a female deity.
Evolution & Gender
Darwin's "On The Origin of Species" was highly influential to evolutionary psychology.
Natural Selection :
the process by which organisms that have advantages in their environment survive while weaker organisms die out.
Survival of the fittest :
the secondary element of evolution that occurs after natural selection. The organisms that survive their environments reproduce and pass on their genes. The organisms that cannot adapt die out and do not reproduce.
Gender Development in Children
Gender typing :
behavior that is largely influenced by society and unconscious. This behavior is where we associated particular emotions, behaviors, and items with one sex while acknowledging the other sex should not use the item (e.g., dolls for girls, race cars for boys).
The same theories that influence morality and aggressive tendencies influence how children form gender beliefs : social learning theory and cognitive-development theory with one extra, gender-schema theory.
By age 2 children have a very firm grasp on different gendered categories.
The younger the child is, the more rigid gender beliefs are. Gender incongruent behavior becomes more common as one reaches adulthood.
Children from ages 3-6 do NOT want to be friends with children who display gender incongruent behavior unless told the behavior is okay.
The average 6 year old child weighs around 45 pounds and is 3.5 feet tall.
Until around this stage of development, boys are traditionally larger than girls. This will change from ages 6-10.
From 6-8 years of age it is expected that children will gain about 5 pounds for each year.
Children also typically grow around 3 inches in height during this same time frame.
Around age 9 girls will start experiencing the first hormones related to puberty. This causes girls to start growing much faster than boys.
Girls, on average, enter puberty around two years earlier than most boys.
Girls storing more fat than boys continues to occur.
Sex Differences in Development
Girls have superior fine-motor skills such as handwriting and drawing.
Girls typically display better balance and agility than boys (due to less muscle?)
Boys outperform girls on all other gross-motor skills (this could be socialized).
Social reassurance for boys improves their abilities in sports.
Girls are implicitly taught to place less value on sports which in turn lowers their performance.
Sports are an amazing way to develop (or inflate) self-esteem and most girls miss out on this source of self-esteem.
Title IX has been highly important to improving girls equal access to physical activities in public schools.
The gender gap in sports is reducing, but still largely exists.
Children easily become aware of unequal treatment if they are taught about it.
Hormones During Puberty
More prenatal development typically indicates earlier growth during adolescence (is this related to hormones receive while in the womb?)
Growth Hormone (GH) & Thyroxine :
the two most important hormones related to physical (muscular and skeletal) development during the initial stages of puberty.
growth hormones related to sexual development. The two most common androgens are estrogen and testosterone.
Remember, both sexes receive testosterone and estrogen, the
the sexes receive are different.
Estrogen is released from a man's testes and a woman's ovaries. In both sexes estrogen is related to an increase in (GH), bone density, and fat accumulation.
When men reach middle age they typically stop producing as much testosterone similar to how menopausal women stop producing estrogen.
Estrogen also causes unique physical development in women such as : breasts, uterus, vagina, and regulation of the menstrual cycle.
Adrenal Androgens :
hormonal glands that rest on top of the kidneys. Primarily influences female growth, but not that important to male development. With women these hormones primarily promotes physical growth and body hair development.
Primary sex characteristics are ALWAYS present, but secondary sex characteristics do not develop until puberty.
Like childhood development, there is variability in amount of time sexual maturation takes, but the order that adolescents experience is normally the same.
a girl's first menstrual cycle. The average age for North American girls is 12.5 and the range is (10-14).
Girls must be physically mature before they experience menarche. This is a "biological prevention" so girls typically cannot get pregnant until their body grows AND they reach menarche.
Girls typically do not release an egg from her ovum for up to the first 18 months of her menstrual cycle. This means they could not get pregnant during this time. It is important to understand that this pattern is NOT across the board!
Sexual Maturity Continued
For both boys and girls, primary and secondary sex characteristics grow first and then body hair typically starts growing.
For boys, the primary form of sexual maturity is the growth of the penis and testes. The range for this growth is typically (12.5 - 16).
Boys' voices deepen due to the larynx and vocal cords increasing in size. During development this is why boys are more susceptible to the "squeaky voice" than girls.
While the penis and testes are growing, the prostate gland and seminal vesicles are growing. The prostate and seminal vesicles are responsible for creating semen.
the first ejaculation a boy experiences. On average it occurs around 13.5 and ranges from (12-16). Spermarche is influenced by social reasons more than the biological reasons of menarche.
Individual Differences In Puberty
Yet again, identical twin studies find that they typically experience puberty at the same time unlike fraternal twins (this supports that genetics influence the onset of puberty).
Girls who are overweight and have a higher storage of fat tend to enter puberty earlier than other girls.
Girls who compete in "weight controlled" sports such as running, gymnastics, or figure skating typically experience puberty much later. These girls may NEVER experience a period if they have 0% body fat. This is very common for women who are anorexic.
The leads into the fact that girls in developing countries with high levels of malnutrition typically do not experience menarche until 14-16.
African-American girls typically experience menarche about 6 months-1 year earlier than Caucasian-American girls.
Scientists cannot agree "why", but we reliably find that children who experience family problems such as divorce, abuse, or rape all enter puberty earlier than children who do not experience this.
The younger the mother, the younger the child enters puberty? Research is still ongoing for this one
You should notice the trend that cultural differences appears to be as strong of a predictor of sex as biology.
Psychological Changes In Puberty
Girls who receive little to no prior information about their menstrual cycle typically report very traumatic experiences during menarche.
Thankfully, with each successive generation, girls are becoming better educated about menstruation BEFORE they actually experience. When this occurs, girls typically do not report as negative of an experience.
The African-American community places less social taboos on discussing menstruation, frame it as a "social milestone of power", and restrict feelings of shame. The reflects in that African-American girls, on average, report the lowest levels of discomfort during menarche.
Considering that menarche is hard enough to discuss, researchers find that boys encounter even less psychological support for spermarche.
Children should NEVER be chastised or shamed when they ask questions about sex. The most important thing is that adults respond appropriately according to the child's age.
countless cultures around the globe have unique rituals related to sexual maturity. While many are VERY GRAPHIC they usually support more stable adjustment to sexual development. American examples include the Bat Mitzvah or the Quinceañera.
Until 1972 public schools were not required to provide equal access to the two sexes (it is not restricted to just sports).
Before Title IX boys outranked girls in both athletics and educational achievement.
From an educational perspective we have to remember that for HUNDREDS of years women were not even allowed to attend higher education. Boys obviously have a very large "head start"
Since the implementation of Title IX, the gap between of boys and girls in physical education has slowly been narrowing.
In just 40 years, girls now outrank boys on ALL areas of academic achievement. Even in STEM fields.
This is very important for the next generation of working women
In 2008, there was still a gender gap in athletic participation. 59% of boys participated in sports whereas 41% of girls participated.
Baby Reveal Parties
happen if we dressed all babies in yellow and purple?
Studies have continued to show that people automatically treat infants different based on color of clothes.
Most common statements :
= such a strong and healthy baby.
= such a pretty and quiet baby.
Color coding babies is primarily an American concept and didn't occur until around the late 1800s.
Originally, boys wore
and girls wore
I have never encountered research, but the textbook implies that this is primarily a Caucasian social behavior.
Adults act very uncomfortable when they do not know the sex of an infant. Why??
Reproductive Success Theory :
Evolutionary theories argue men are concerned about quantity of offspring and women care about quality of offspring.
Evolution theories argue that reproductive differences encourage men to be "roamers" while women are less capable of multiple partners due to pregnancy and child rearing.
This statement has often been used like religious statements to encourage male promiscuity and female chastity (i.e., the double standard).
Current opposing theories
"Variation within each sex is greater than differences between the sexes" (Hyde, 2005)
Are differences "real" if taught by society and not biological?
genders are different due to sexual selection that "preserves" different adaptive traits to males and females (Buss, 2003)
Aggression,status, and earning power for men
Attractiveness, caring, and nurturing for women
Buss (1990) studied participants in 37 countries that supported these findings
When excluding sex as a variable, overall the most desired charcteristics across the globe were kindness and love
A Natural History of Rape (?)
A Natural History of Rape
is a very controversial evolutionary book which argues rape is an evolved response.
Remember, evolutionary theories and reproductive success theory argues that men try to produce offspring.
The natural rape theory argues that men are willing to do anything, even rape, to pass on their DNA.
"Rape is the evolutionary mating strategy of losers, males who cannot otherwise get a date. Rape is an alternative to romance; if you can't always have what you want, you take what you need" (Kimmel, pg. 28, 2013).....
Are physically weaker or unattractive men more likely to rape? Who do we typically imagine as the stereotypical rapist?
Using natural selection they say women evolved and learned how to deny men. In response to this, men "evolved" the ability to rape women that say no.
This is a dangerous statement because it justifies criminal behavior that impacts the victims life forever.
Rape and Sexual Assault
There is a very large disconnect between "common knowledge" and empirical research on sexual assault.
Many universities are uncomfortable mentioning that university campuses are one of the most common places that sexual assault occurs.
1 in 6 women will experience rape or attempted rape in her lifetime.
Like many other "hot button" issues, only 1 in 5 rapes are reported. Therefore, the rates are much higher than estimated.
32,000 rapes result in pregnancy every year and 3% of reported rape cases result in STD infections.
DO NOT BELIEVE THAT MOST RAPE OCCURS BY RANDOM STRANGERS!!
75% of women who report rape state that the perpetrator is somebody they know (primarily their husband, intimate partner, or friend).
10-14% of women experience marital rape
25% of all college females will experience sexual assault during their time at college.
Acquaintance (Date) Rape :
common form of rape among college students where women feel extreme pressure into performing sexual acts.
Rape Myths and Realities
A woman who appears alone and dresses provocatively is "asking for it"
When a woman says "no" she really means "yes"
Many women who are raped enjoy it.
If a woman goes home with a man, she is interested in sex.
If she is sexually active, she is lying about rape.
America's male dominated society is a "rape culture"
Rape Victims often receive more "punishment" from the justice system than the rapists.
Victims have to "prove they were raped" instead of "proving the criminal raped me".
Men who believe rape myths are more likely to commit sexual assault.
Sociobiology vs. Sociology
the interdisciplinary field that combines biology and sociology to explain how DNA influences our behavior in society.
Sociologists want to explain behavior through cultural interactions.
Sociobiologists would argue that our genetic coding makes us more "predisposed" to certain environments.
Using this perspective, a person who has genetic makeup for athleticism would be drawn or attracted to a culture that gives them a genetic advantage.
Gene DRD2 :
if people have this gene they are more likely to experience alcoholism.
Sociologists would say that people abuse alcohol because society is causing them stress or unhappiness (e.g., no job, wealth inequality, etc).
Sociobiologists would argue that the presence of the Gene DRD2 would make the person more likely to visit bars, drink at parties, or actively seek out alcohol.
"Genes do not determine people's behavior. Rather, their experience is modified by social experiences. On the obvious level, Arabs with the Gene DRD2 who live in a society where alcohol is difficult to find are less likely to abuse alcohol than are Americans with this gene who hang around bars" (Henslin, pg. 60, 2015).
Animal Sexual Behavior
Remember, when studying animal behavior we do not define sex and gender.
Gendered behavior is something that is restricted to humans. Animals only display sexual characteristics.
People often try to place gendered behaviors on animals to match their specific sex.
Most biologists argue that almost all animals operate in male-dominated societies. The most popular examples of patriarchal animal societies are chimpanzees, bonobos, and elephants.
Sometimes the argument that "since males dominate females in the animal world, it must be natural".
Using that argument....almost all biologists would quickly say that homosexuality is a natural phenomenon in the animal kingdom.
Primates, elephants, giraffes, penguins, sheep, dolphins, and whales have all been recorded practicing same-sex relations among animals.
No studies have depicted animals keeping a same-sex partner throughout it's lifespan. Of course, very few animals are monogamous for life, heterosexual or homosexual.
The most common form of studying animal sexual behavior is to examine reproductive behavior.
As stated early, the primary goal would be to NOT place human characteristics on animal behavior.
Development of Sexual Behavior
Nerve cells attached to sexual organs are active at birth. Kinsey's research verifies that these nerve endings do not develop at puberty like originally believed.
The important aspect is that just because these physiological structures are fully formed, psychologically they are not ready for any form of physical intimacy.
Like many processes in the body, sexual arousal is not controlled by one single system in the body.
Erogenous Zones :
Stimulation of erogenous zones typically leads to an increase in sexual arousal. You are college students, I don't need to tell you the specific places.
Medical examinations and rape are examples used to highlight that in certain situations stimulation of the erogenous zones do NOT produce pleasure. This leads us to believe it is not all physical stimulation.
Supporting the previous statements, it is common knowledge that people can become sexually aroused without the presence of any physical stimulation
Sexual Scripts :
schemas that are specifically related to sexual behavior. "The Rules of Sex". There is diversity among different cultures.
Men and women do not differ on sexual arousal, social expectations of women typically force them to dismiss many desires.
Average American Sexual Behavior
A man's sexual peak is at 18 whereas a woman's peak is at 30-35.
Monogamy is, by far, the most common mate selection pattern.
Men's level of masturbation remains stable throughout life. More women admit to masturbating from ages 27-50.
Around 40% of the population refuse to answer the question
Sex Drive :
a measurement of sexual arousal that is unique to each individual. Primarily measured by how sensitive a person is to the sex hormones they are producing.
Being tipsy lowers inhibitions which makes it easier to flirt. Being drunk typically leads to...failure.
A Hodge-Podge of Female Sexuality
Historically, medical doctors used to argue women did not experience sexual pleasure.
In older times, men argued that women's genitalia was only related to reproductive success.
Today, researchers know that the clitoris is responsible for around 75% of a woman's sexual pleasure (Why am I telling you this?)
The clitoris has no connection to reproduction, so yes, women do have naturally occurring organs that are responsible for sexual stimulation.
This may also help explain why some African cultures perform a clitorectomy on women, to remove any chance of sexual pleasure.
Some evolutionary studies argue that women experience a higher level of arousal during menstruation.
One study found that women, if in a relationship, think about infidelity more while they are menstruating.
"What's more, in cultures where artificial light is not used, all women will tend to ovulate at the full moon and menstruate at the new men" (Kimmel, pg 33., 2013).
Sex and Neuroscience
As mentioned in class, scientists used to believe that men had larger brains.
Now we know that brain size is relative to body size in humans. In other words, a woman and man of similar weight/height will have comparable brain sizes.
Researchers also used to argue that Caucasians had the largest brains and African-Americans had underdeveloped brains. These studies have been discredited for decades now (read : no differences between brains sizes and races).
One fallacy of early neuroscience research is that they had a strong desire to prove their hypotheses. This goes directly against objectivity in scientific research
This implies that male researchers wanted to find sex differences in the brain, this strong desire unconsciously pushed them towards always explaining results in sex differences.
Lateralization and Brain Plasticity
the process by which the two hemispheres have specialized functions.
Believed to be a product of natural selection because it allows us to adapt to environmental pressures better.
Essentially, it allows the brain to multitask and be more productive than if the brain did not have specific functions.
Using a sports analogy (gasp!), it would be like if every football player tried to all be the quarterback.
the infant brain is not lateralized yet and capable of change (i.e. highly plastic). This way the brain can adapt and other areas can take over if specific areas are damaged.
Once the brain becomes lateralized it is not able to adapt to changes of the brain anymore.
There is also a believed relationship between synaptic connections and brain lateralization.
Origins of Sexual Orientation
Genetic research demonstrates that sexual orientation may be influenced by the X chromosome (i.e., maternally influenced)
Recent evolutionary arguments state that homosexuality developed as a form of population control for mate competition.
Prenatal hormonal theory of homosexuality :
It argues that gay males did not receive enough testosterone in the womb and lesbians receive too much testosterone during fetal development.
It is important to understand that this hormonal difference is completely gone by adulthood and hormone levels cannot accurately measure sexual orientation in adults.
Neuroscience & Sexual Orientation
There is one infamous study (LeVay, 1993) that reported homosexual and heterosexual men had different brain sizes. This study gained international recognition.
After a couple of years a different researcher replicated the study and
did not report
the brain difference between heterosexual and homosexual men.
Along comes an American Medical Association publication which reports that people with AIDS experience brain degeneration.
A separate researcher contacts all homosexual participants in LeVay's 1993 study and discovers all of the participants were people with AIDS.
Therefore we now know that sexual orientation does not cause a difference in brain size, but AIDS can cause brain degeneration reducing the size of brains.
More recent research shows that the hypothalamus, an area responsible for sexual activity, does differ in size for transgendered people.
Typically, all neuroscientific now "controls for" diseases that cause neurological damage so faulty research is not conducted.
This may not be natural and the result of Hormone Replacement Therapy.
From an anthropological perspective, homosexuality is not a new phenomenon. Evidence has been found all the way back to the Paleolithic Period of mankind (10,000 B.C.).
You need to remember that any estimates of sexual orientation are
Survey data estimates that 4% of Americans view themselves as homosexual or bisexual. This equates to 12 million people in America.
Homosexual adolescences often approach sexual relationships later than heterosexual adolescences due to cultural norms.
How do we classify people that have homosexual desires but NEVER ACT on them?
This is one common "cultural myth" that we have about sexual orientation. One act does not determine sexual orientation. It is a repeated, consistent trend of behavior that determines sexuality.
The most glaring differences among different sexual orientations is commonly attributed to social treatment.
Differential Treatment in Society
It is still legal to fire or not hire a person because of sexual orientation in 18 states. It is legal in South Dakota to fire or refuse employment to somebody based on sexual orientation.
This discrimination also extends to housing and medical benefits.
LGBTQ teenagers have the highest homelessness rate and highest truancy problem of any other teenage groups.
18 states have no hate crime protections for homosexual people. There is a link between state protections and hate crime occurrences.
The American Psychological Association officially removed homosexuality as a mental disorder in 1975 and being transgendered was just removed in 2014.
As previously mentioned in class, conversion therapy is illegal in many states, but yet again, the same states that have no hate crime or discrimination protections also allow children as young as 10 years of age to undergo sexual conversion therapy.
Social rejection for
any minority group
typically leads to higher rates of : anxiety, depression, substance abuse, risky sexual behavior, and suicidal thoughts.
Gay men are the second highest at-risk group for suicide. The highest group are elderly widowed men over 65+. For gay men, as one ages, the chances of suicide typically decrease.
Homosexual people tend to create stronger "social buffers" to help offset the social rejection and discrimination they commonly experience.
Dimensions of Sex
Ways to Determine Biological Sex:
Genetics (XX, XY, or other combinations)
Hormonal Sex :
the chemical composition of sex specific hormones. Men and women typically receive different sex hormones from the adrenal glands.
Gonadal Sex :
the presence of ovaries or testes.
Genital Sex :
the presence of the clitoris and vagina for females; the presence of the penis and scrotum in males.
Medical doctors use these four measurements to fully establish the child's sex. We will come back to how important this is.
Hormonal and Gonadal Sex
Scientists used to think that nothing would override genetic sex, but this is NOT the case.
During prenatal development the fetus is being bombarded with very high amounts of sex hormones.
the sex hormones that influence sexual development for males. The most common androgen is testosterone.
the sex hormones that influence sexual development for females. Estriol is the most common form of estrogen.
The sexual organs that secrete either androgens or estrogen. It is the testes in men and ovaries in women.
Men and women have BOTH androgens and estrogen. It is the amount or level of the hormones that determines sex.
Some researchers take a "male-centric perspective" that states sexual development is completely due to the absence or presence of testosterone.
For the first six weeks of fetal development there are no sexual characteristics in the fetus.
It's a little more complex than just that!
Imagine this situation : the fetus received the XY sex chromosomes from their parent. Next, the child does not receive enough testosterone in the first six week. This causes the male fetus to be born without male genitals. Sexually, how do we label the person?
Androgen Insensitivity :
genetic defect where the developing fetus does not respond to the presence of androgens during prenatal development. This child, even if they have the XY genes, will develop into a girl.
pharmaceutical drug that prevents spontaneous miscarriages. This drug was later linked to female infants being born with male genitals.
Androgenital Syndrome :
this is the disorder that female fetus' develop when they are exposed to progestin.
These disorders are very complicated considering that, for the most part, INTERNAL sex organs are more likely to develop abnormally (e.g., a male with ovaries or a woman with internal testes).
This leads us to suspect that thousands of people throughout history were either androgen insensitive or had androgenital syndrome and never knew it!
How would a man KNOW he had internal ovaries if he has never received an X-ray? Keep in mind that the unintended sex organs are usually sterile (e.g., men with ovaries do NOT menstruate)
Papua new guinea is known to have some of the most sexually explicit initiation ceremonies.
Sexual Orientation :
of emotional and sexual attraction to a specific sexual category.
being attracted to the opposite sex
being attracted to the same sex. Estimates place homosexuals @ around 10% of the global population (Kinsey, 1948; Gates, 2011).
being attracted to both sexes.
If heterosexual people cannot remember when they first were attracted to the opposite sex, is it appropriate to ask a homosexual or bisexual person this?
Direct quote from a textbook (Coon & Mitterer, 12th edition, pg. 422).
The textbook authors give these interesting arguments about
between different sexual orientations :
Sexual Orientation is a deep part of personal identity. Starting with their earliest erotic feelings, most people remember being attracted to either the opposite sex or the same sex. The chances are practically nil of an
heterosexual or homosexual person being "converted" from one orientation to the other. If you are heterosexual, you are probably certain that nothing could ever make you have homoerotic feelings. If so, then you know how homosexual persons feel about the prospects for changing their sexual orientation.
Biological research by many different scientists have started reporting that there may be relation between sexual orientation and our genes.
One study found that if one identical twin is homosexual or bisexual, there is a 50% chance that the other twin is too. Similar findings lead some researchers to estimate that sexual orientation is 30 to 70 percent genetic (Mustanski, Chivers, & Bailey, 2002).
Acknowledging this reliable research, how can we say that same-sex couples will "turn" their children gay?
no sexual attraction to either sex. There are many misconceptions about people who are asexual. Many asexual people have healthy, romantic relationships. Very few people are asexual because of traumatic sexual abuse.
3.5% of Americans identify as Gay, Lesbian, or Bisexual (Gallup, 2002)
The more accepting a society is of different sexual orientations, we may find more accurate estimates.
Some people may participate in homosexual or bisexual behavior but not identify as such.