Lecture 2 –September 10, 2003
Tonight we look at biological theories used to explain gender. We recognize that there are physical differences between men and women. But why should that be important?
We know that males and females are identical in their development until the sixth week of gestation, when genetics, along with various hormones, come into play to help produce those physical differences between the sexes. However, several questions remain: Do chromosomes or hormones contribute in any way to the behavioral and personality differences we often observe between males and females? If so, to what extent. And given that theses are biologically based differences, are they immutable.
What we should recognize is that the search for the origins of behavioral and personality differences rooted in the biological makeup of the individual is actually an argument used to explain and justify the inequality between men and women. If the difference between men and women is biological and our biology is immutable, rectification of inequality cannot be achieved.
The same arguments are used for and against homosexuality – looking for a gay gene or a gay brain or the gay hormone. In the past, psychologists and sociologists used to use these arguments to explain inequality among races, e.g. the “black, yellow and white” brain.
We will look at the three types of biological arguments. Both Robert Sapolsky and Anne Fausto-Sterling are respected biologists.
Basically three types of biological arguments to explain gender differences:
1. Chromosomal (genes)
2. Hormonal –
3. Brain structure
(1)The influence of sex chromosomes. Before an egg is even fertilized, chromosomal errors can occur during sperm production that later result in the birth of individuals with an abnormal complement of sex chromosomes.
This can take place in the two-stage process of sperm production called meiosis. The division of sperm usually produces two kinds of sperm - those that carry a Y chromosome and those that carry an X chromosome. Sometimes the sperm fail to divide properly. - This is called nondisjunction. If nondisjunction occurs during the first meiotic division (stage one) two kinds of sperm are produced: Those with both an X and a Y, and those with neither an X nor a Y. If one of these sperm fertilized a normal egg, the off spring with be either XXY or XO.
If nondisjunction occurs during the second stage of meiotic division) three kinds of sperm are produced: XX, XY and those with no sex chromosomes. Eggs fertilized by these sperm would produce offspring that are XXX, XYY, and XO respectively.
For our purposes, we want to know if these chromosomal abnormalities have any effect on gendered behavior or personality traits?
Turner syndrome (XO) Because they do not have a Y chromosome, they do not develop as males. However, without a second X chromosome, they have no gonadal tissue and produce no sex hormones. They are reared as females because their external genitals appear to be female. Studies have shown them to be exhibit an exaggerated femininity in their behavior and personalities. BUT there is no biological explanation for these behavioral and personality differences. Instead, it may be that parents of Turner syndrome girls, determined to compensate for the missing X chromosome, intensified the feminine socialization of their daughters.
XXX women - show few visible signs of abnormality, although they tend to be taller than XX women do and have a higher incidence of learning disorders.
Klinefelter - XXY chromosome combination. Individuals with Klinefelter syndrome physically look more male than female, although they usually have small penises and testes. At puberty, although they tend to grow taller than average, their hips usually feminize, they may have some breast development, their testes do not enlarge, they do no produce sperm, their voices do not deepen, and they develop little or no public and facial hair. It has been reported that these men tend to be timid and socially isolated; at an increased risk for developing emotional and interpersonal problems, and uninterested in women, dating or sex. However, we could argue for a social cause. Perhaps, the problems result from individuals' trying to cope with their abnormality in a society that is not especially kind to any kind of deviation;
nevertheless, most researchers report that many XXY men are no different from XY men in terms of social and emotional characteristics.
XYY Syndrome - interest because research reports showed an unusually high incidence of the abnormality among institutionalized and incarcerated men. Why would having an extra Y-chromosome predispose men to behave violently? The Y chromosome is associated with the secretion of the hormone testosterone, which has been linked with aggression. Consequently, it was hypothesized that an extra Y chromosome would lead to elevated testosterone levels, which in turn would increase the likelihood of aggressive, even violent behavior. However, subsequent research showed that XYY offenders committed primarily petty property crimes and that rather than being especially aggressive, they were somewhat less aggressive than chromosomally normal men were. XYY men do not appear to have elevated testosterone levels. XYY tend to be unusually tall and have a low level of intellectual functioning that may serve to explain their high level of incarceration.
Sociobiological theories and evolutionary psychology fit into this focus of genes - According to sociobiologists all species have a biological imperative to reproduce their genes. Males and females of species develop different reproductive strategies in order to reproduce their genes. For the male, reproductive success depends upon his ability to fertilize large numbers of eggs. Toward this end, he tries to fertilize as many eggs as he can. Thus males have a “natural” propensity toward promiscuity. By contrast, females require only one successful mating before their egg can be fertilized, and therefore they tend to be extremely choosy about which male will be chosen. Females must invest a far greater amount of energy in gestation and lactation, and have a much higher reproductive “cost” which their reproductive strategies would reflect. Females therefore tend to be monogamous, choosing the male who will make the best parent. “A woman seeks marriage to monopolize not a man’s sexuality, but rather, his political and economic resources to ensure that her children (her genes) will be well provided for.”
The sociobiologist uses this theory to explain supposed differences in men and women based on their chromosomal differences. Accordingly: women generally prefer older men as mates, while most males prefer younger females. In courtship and mating behavior, most men are more sexually aggressive and most women are more coy. Males are more inclined to delay marriage. Men are more likely to seek a variety of mates. Women tend to be more tolerant of adulterous mates. Females are more likely to be domestic and nurturing. Sociobiologists argue that men who rape are fulfilling their genetic drive to reproduce in the only way they know how.
Animal biologists inform us differently - some species are polyandrous, (chimpanzees) some are sexually exclusive. Some females actively solicit males when they are not ovulating.
The newest incarnation of sociobiology is called “evolutionary psychology.” Which declares an ability to explain psychological differences between women and men through their evolutionary trajectories. Men are understood to be more aggressive, controlling, and managing – skills that were honed over centuries of evolution as hunters and fighters. After an equal amount of time raising children and performing domestic task, women are said to be more reactive, more emotional, and more passive. Hence, Talcott Parsons structural functionalism…. And Popenoe’s argument that fathers can’t be nurturant.
Michael Kimmel asks us “do these evolutionary arguments make sense? Does their evidence add up to basic irreconcilable differences between women and men, made necessary by the demand of evolutionary adaptation.” He argues that it is based on an interpretation of evidence that is selective and conforms to preconceived idea.’; We read backwards, for example that men are more likely to be promiscuous and then read it back to our genetic coding.”
What Judith Lorber calls, "Believing is Seeing" We believe first, then find (see) data that fits our belief. These are arguments that remain empirically untestable. Some sociobiological arguments are based on selective use of data, ignoring those data that might be inconvenient. For example, baboons seem to be female-dominant. The female chimpanzee has sex with lots of different males.
“Maternal instinct” - How do we explain the enormous popularity of infanticide as a method of birth control throughout Western history, and the fact that it was women who did most of the baby killing?
What about the sociobiological argument that rape is simply sex by other means for reproductively unsuccessful males? Such arguments ignore the fact that most rapists are not interested in sex but in humiliation and violence, motivated more by rage than by lust. Most rapists have regular sex partners; quite a few are married. Many women will outside of reproductive age, either too young or too old be raped. And why would some rapists hurt and even murder their victims thus preventing the survival of the very genetic material that they are supposed to be raping in order to pass on. And why would some rapists be homosexual rapists, passing on their genetic material to those who could not possibly reproduce? And what about rape in prison?
Kimmel says we can use the same evidence and construct a different argument. From this evidence one might adduce that human females are uniquely equipped biologically – indeed, that it is their sexual strategy – to enjoy sex simply for its physical pleasure and not for its reproductive potential. And if the reproductive goal of the female were to ensure the survival of their offspring, then it would make sense for her to deceive as many males as possible into thinking that the offspring was theirs. That way, she could be sure that all of them would protect and provide for the baby, since none of them could risk the possibility of his offspring’s death and the obliteration of his genetic material.
Fausto-Sterling - XX babies grow up to be female while XY become male according to geneticists because of the Sex-Determining Gene on the Y . Biologists also refer to the SDY Gene on the Y as the “Master-Sex-Determining Gene” and say that in its presence a male is formed. So that females are said to be the default sex. Fausto-Sterling wants us to recognize the introduction of value into the biological argument.
A second focus of biological theories is the role of hormonal activity in shaping gender-related behaviors.
Mullerian Inhibiting Substance suppresses the development of internal female organs while fetal testosterone help to develop both the internal and external trappings of physical masculinity. “Males requires their presence of special hormones; in their absence, femaleness just happens.” “Masculinity is this view is an active presence which forces itself onto a feminine foundation.” (“The Adam Principle.” Fausto-Sterling
During the sixth week of pregnancy, the presence of a Y chromosome in a fetus caused the indifferent gonad to develop into testes, which produce a group of hormones called androgens that, in turn, promote the formation of male sexual organs and genitalia. What if a female fetus gets exposed to androgens?
Adrenogenital syndrome (also called congenital adrenal hyperplasia). Can be caused by a malfunction in the mother's or the fetus's adrenal glands or from exposure of the mother to a substance that acts on the fetus like an androgen. Genetic females - the androgens have a masculinizing effect on their external genitals (i.e. the clitoris is enlarged and may resemble a small penis, the labia may be fused, and the vagina may be closed). Because their internal reproductive organs are normal and they are often fertile, surgery is typically used to redesign their external genitals so they are consistent with their genetic sex. AGS females also usually undergo hormonal replacement therapy, so they experience normal female pubertal development. The studies on behavioral traits are conflicting - some researchers have found differences between AGS and non-AGS - examples AGS prefer slacks and shorts to dresses and skirts. They like toys considered more appropriate for boys. Nevertheless other researchers do not see increased aggression, appear to be sexually oriented to males.
Biologist Anne Fausto-Sterling argues that the research has several problems – first no independent measure of the effects of AGS – just reports by parents whose observations, one can argue, were biased by the differential treatment of their very “different” children (example – clitoridectomy)
Genetic males - Androgen-insensitive syndrome. Happens when an XY fetus has a genetic defect that causes it to be unresponsive to the androgens its testes secrete. These individuals are sometimes referred to as XY females because even though they possess the sex chromosomes of normal males (XY), they are born with the external genitalia of females. They look like girls at birth, so they are typically raised as girls by their parents. In fact, their condition is sometimes not discover until puberty when, because they have no uterus, they do not menstruate. According to researchers, androgen-insensitive individuals are as feminine and sometimes more feminine than normal XX females.
Another condition, which involves partial rather than total androgen insensitivity, is DHT deficiency syndrome. (Also called 5-alpha-reductas deficiency). In individuals with this condition an enzyme (5-alpha-reductasae) responsible for converting testosterone into DHT (dihydrotestosterone) is abnormally low or absent. DHT is the hormone that prompts the formation of the external genitalia - the scrotum and the penis. Individuals low in DHT or who lack it completely are born with normal undescended testes and internal male accessory organs. Externally, they have female genitals that are partially masculinized (an enlarged clitoris that resembles a small penis and sometimes an incomplete scrotum that looks similar to the female labia). Because of the presence of normal testes, however, at puberty, when the testes begin to produce large amounts of testosterone, the external genitalia change. The penis grows, the scrotum descends, and the body becomes more muscular. What happens to an individual who is raised as a girl suddenly becomes a male? In the Dominican Republic, there are a higher number of these individuals in a rural village who have been studied. According to Imperato-McGinley these boys don't have problems because their brains having been exposed to prenatal testosterone, has been masculinized in utero, thus allowing them to quickly ignore or reject seven to twelve years of socialization as a female.
However, other researchers say these girl-boys are treated differently during childhood with the expectation that they will be males. And also, is not being male the more preferred gender?
Case of boy who was chromosomally and physically normal male until 8 months old when a medical accident occurred as a doctor tried to repair the foreskin. At 17 months old, the child was reassigned genders and was surgically reconstructed as a girl and life long hormone replacement therapy was planned. During his adolescence, the child began to have emotional problems and at 14 chose not to take hormonal treatments. At young adulthood, she decided to undergo male hormone therapy and a mastectomy and had a penis surgically constructed. At 25 he married a woman. What does this say? ? Diamond and Sigmundson's controversial explanation as to why this child could not be "successfully" socialized as a girl was that her brain had been exposed to the male hormone testosterone, making her irreducibly male. No matter how hard people worked at making her female, her brain knew otherwise.
Other explanations are just as valid. The child was treated differently than her brother. Her parents worked very hard to make her “the best little girl.” She was large and not very feminine in appearance and resented having to take hormones.
Testosterone and Gender -The question is does the secretion of testosterone also produce a male brain which in turn, generates those distinctive personality traits and behaviors that we, in our culture, associate with masculinity?
Sex differentiation faces its most critical events at two different phases of life: 1) fetal development, when primary sex characteristics are determined by a combination of genetic inheritance and the biological development of the embryo that will become a boy or girl and 2) puberty, when the bodies of boys and girls are transformed by a flood of sex hormones that cause the development of all the secondary sex characteristics.
Steven Goldberg “the hormonal renders the social inevitable.”
Geschwind and Behan found that during fetal development it is the “testosterone bath” secreted by slightly more than half of all fetuses that begins sex differentiation in utero. The testosterone bath selectively attacks the left hemisphere that is why males favor the right hemisphere.
We should remember that women and men have both testosterone and estrogen, although typically in different amounts. On average, men do have about ten times the testosterone level that women have, but their range among men varies greatly and some women have levels higher than some men do.
On the surface, the experiments on testosterone and aggression appear convincing. Males have higher levels of testosterone and higher rates of aggressive behavior. Castrate him and his aggressive behavior will cease
But Robert Sapolsky warns against such leaps of logic.
He gives us several bits of research to help us understand that aggression is a very complex concept. He says that the level of aggression is likely to plummet in castration. However, if you reinstate only 20% of the testosterone level, the precastration level of aggression returns. If you introduce twice the testosterone levels, the same level of precastration level remains. Anywhere from roughly 20% to twice normal and it’s all the same level of aggression.
Example 5 male monkeys arranged in a dominance hierarchy from one to five, The top monkey’s testosterone level will be higher than the ones below him and levels will decrease down the line. Number 3 will pick fights with numbers four and five, but will avoid numbers one and two. If you give number 3 massive infusion of testosterone, he will likely become more aggressive – but only numbers 4 and 5. He will still avoid numbers 1 and 2. Sapolsky says “testosterone isn’t causing aggression, it’s exaggerating the aggression that’s already there.
It turns out that testosterone has what scientists call a “permissive effect” on aggression: It doesn’t cause it, but it does facilitate and enable the aggression that is already there.
Sapolsky notes that the levels of aggression do not drop to zero in castration. Social conditioning can more than make up for the absence of the hormone. The more social expereinc an individual had being aggressive prior to castration, the more likely that behavior persists even after castration.
Testosterone is produced by aggression.
Theodore Kemper – Both women and men’s testosterone levels rise after winning – concept of “eminence," where elevated rank is earned through socially valued and approved accomplishment.”
The evidence linking testosterone to aggression has come primarily from animal studies. However, there is tremendous variation in behavior across animal species (for example, female hamsters). In research with humans, findings do indicate that high levels of circulating testosterone are correlated with edginess, competitiveness, and anger. This result holds for both men and women. However, scientists have not been able to pinpoint the relationship between testosterone and specific behaviors in humans for a number of reasons. One is that the hormone fluctuates dramatically over the course of a day and in response to environmental stimuli.
Scientists have had difficulty specifying more precisely the relationship between testosterone and human aggression because testosterone is only one of several chemicals interacting with the body that affect human behavioral response. Two other important chemicals are the neurotransmitters serotonin (calming) and noradrenaline (response to crisis)
Research indicates that human social behavior is highly governed by the situation or contest in which it occurs, and that this, in turn may override or alter the potential effects of various hormones. Studies with women show that they can be just as aggressive as men in certain situations such as can when they are rewarded for behaving aggressively or when they think no one is watching them.
Cross-cultural research indicates that women may behave as aggressively as men but how they express aggression (verbal vs. physical aggression) may be structured by their culture's gender.
Finally, physical aggression is not observed in middle and upper class males as readily as in lower economic classes.
Women, Hormones and Behavior. PMS. - Scientific evidence is scant. Although it is popular in the press and with the APA (late luteal phase dysphoric disorder) Methodologies flawed - retrospective studies rather than prospective studies. Patients are as likely to report feeling better after taking sugar pills as they are after a dosage of vitamin B6, progesterone, or even Prozac. (All treatments for PMS).
Postpartum Depression - the exceptionally low incidence of postpartum depression and psychosis reported in cross-cultural studies indicates that sociocultural or environmental factors may also be important contributors to depression and psychosis.
A third focus of biological theories of difference is brain structure and development, which appear to be linked to sex. The notion that men and women have different brains is an old one. 19th century scientists maintained that women were less intelligent than men were because their brains are smaller - but then what about elephants? It was subsequently argued that the best estimate of intelligence could be obtained by dividing brain size by body weight. But by this calculation women would be smarter. Currently, the research is on how the brain is organized.
Contemporary brain research has focused on three areas: 1. The differences between right and left hemisphere; 2. The difference in the tissue that connects those hemispheres and 3. The ways in which males and females use different parts of their brains for similar functions.
First problem in this line of thinking: research uses the brains of animals not humans.
Second problem is that the human brain changes as people age and response to experience and environmental conditions.
For example, although men's brains are, on average, larger than women's brains, men lose brain tissue three times faster than women as they age, but it unclear at this pint. Why. New nerve growth can be stimulated in the brains of both elderly women and men by introducing new challenges into their environment. Emotional trauma can structurally change brains. As well as cognitive therapy.
A third related problem is that scientists do not yet fully understand how the way specific parts of the brain are structured affects how they function. Some scientists speculate that the relationship may actually be the opposite of what we might think: Instead of structure determining function, the way the brain works causes it to build or alter its structure.
Apparent differences - Brain lateralization. The left hemisphere controls the right side of the body is responsible for language, among other things. The right hemisphere (which controls the left side of the body) is thought to handle such functions as emotions. Women who suffer from strokes tend to recover more quickly than men. It was hypothesized that the reason for this difference by be that men are more lateralized than women - that is, they are more dependent on one hemisphere of their brains to complete certain tasks, whereas, women draw on both hemispheres. MRI research seems to confirm this.
Second type of research is related to the corpus callosum - the mass of tissue and nerve fibers that connect the two hemispheres of the brain is as much as 23% larger in women than in men. It may be that the greater size of women's corpus callosum allows more communication between the brain's two hemispheres. So theories - women out perform men on tests of verbal ability, while men outperform women on tests of spatial ability. Women may be better listeners or maybe they have to use both parts of the brain to accomplish what men do with one hemisphere.
Depending on what you want to "prove," the biological is used to explain the social. Greater communication between the two hemispheres may facilitate verbal skills, but research also shows that such cross talk may impede spatial skills. This knowledge is used to point out that "women are less able to compartmentalize their emotional responses from their rational analytic behavior." But Katherine Donnato points out that women dominated computer programming in the 1940s. Our brains didn't change - but social structure did.
However, Renzetti and Curran say we could argue that through socialization women and men learn throughout their lives to process language and interpret spatial relationships differently, and their brains have adapted to these socialization experiences.
Carol Tavris reminds us that the belief that men and women’s brains differ in fundamental ways has a “long and inglorious history.” Researchers keep changing their minds about which lobe of the brain accounted for male superiority and which hemisphere of the brain accounts for male superiority.
Originally the left hemisphere was considered the repository of intellect and reason. The right hemisphere was the sick, bad, crazy side, the side of passion, instincts, criminality and irrationality. So there was “evidence’ that men were right-hemisphered.
In the 1960s and the 1970s the right brain was rediscovered. Scientists began to suspect that it was the source of genius and inspiration. Now men were considered to have “right-brain specialization.”
Then Delacoste Utamsing “the female brain is less well lateralized – that is, manifests less hemisphere specialization than the male brain for visuospatial functions.” Therefore, women do well in verbal; men in spatial.
Gender differences in cognitive abilities keep changing – in last 30 years gender differences in mathematics scores have declined sharply. When exposure to mathematics is controlled there is not significant difference.
Problems with brain studies:
The studies are small and inconclusive.
The meanings of terms like “verbal” and “spatial” abilities keep changing, depending on who is using them and for what purpose.
There is far more convincing evidence for sex similarity is rarely published.
Instead of looking for gender differences, Renzetti and Curran discuss a transformative account of gender development - one that examines how culture and individual behavior may impact biology and physiology as well as vice versa. The social can affect the biological - diet, exercise, being allowed to participate. Although we may inherit a tendency toward a particular body shape, most women's weight can change considerably in response to our diets, levels of physical activity, and other patterns of living. These also affect physical fitness and strength. When women begin to exercise and engage in weighs training and body building, we often notice surprisingly greater changes in strength to even quite moderate training. Women's times in running have deceased dramatically over the last 20 years. The biochemistry of the brain has been shown to change under social conditions - examples include severe abuse as well as cognitive therapy. The body itself - examples of severe, emotional stress can create instances of failure to thrive
Anne Fausto-Sterling
“One of the very interesting things about biological investigators. They use the infrequent to illuminate the common. The former they call abnormal, the latter normal. And the abnormal requires management.” Management means conversion to the normal.
Irony – “Biologists and physicians use natural biological variation to define normality. Armed with this description, they set out to eliminate the natural variation that gave them the definitions in the first place.”
According to John Money (Johns Hopkins – where sexual reassignment was studied intensively). To become either a true male or a true female in John Money’s world, one must produce the right hormones at puberty (pubertal hormonal sex) acquire and express a consistent gender identity and role, and, to complete the picture, be able to reproduce in the appropriate fashion (procreative sex).
Fausto-Sterling notes the value-laden judgment in sex-reassignment masquerading as value-free science. Genetically females should always be raised as females, preserving reproductive potential, regardless of how severely the patients are virilized. In the genetic male, however, the gender of assignment is based on the infant’s anatomy, predominantly the size of the phallus. Patricia Donahue, David Powell, and Mary M. Lee “Clinical Management of Intersex Abnormalities,” Current Problems in Surgery 8 (1991), 527 quoted in Fausto-Sterling.
In summary what do we learn from genital ambiguity? The development of a masculine of feminine gender identity is quite independent of either the presence of a pair of XY or XX sex chromosomes or the production of particular hormones. More importantly, this research indicates that neither sex nor gender is dichotomous. When we speak of sex, we may be referring to chromosomal sex, hormonal sex, gonadal sex or genital sex.
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