Lecture 3 - 1/31/2001
Biology, Sex, and Gender: The Interaction of Nature and Environment
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?
The argument used to explain and justify the inequality between men and women is essentially a biological one. If the difference between men and women is biological and our biology is immutable, rectification of inequality can not be achieved.
One focus of biological theories is the influence of sex chromosomes.
Use this for background information. Most males have an XY chromosome while most women have an XX chromosome structure.
Basic biology - Around the sixth week of embryonic development the process of sexual differentiation. Until then the XX or XY embryo is sexually bipotential.
During the first six weeks, the embryo develops a gonad called the indifferent gonad - looks the same in XX and XY embryos. Two sets of ducts - one female the Mullerian ducts and one male the Wolffian ducts.
During week six - something happens SRY (sex-determine region of the Y) seems to stimulate the transformation of the indifferent gonad into fetal testes. Once developed, the fetal testes begin to synthesize a whole group of hormones called androgens. One inhibits the Mullerian duct system, and testosterone that promotes further growth of the male (Wolffian) duct system.
DHT (dihydrotestosterone) during the eight week prompts the formation of the external genitals.
Scientists are even unclear of how the XX fetus becomes sexually differentiated.
Chromosomal abnormalities and gender.
Before an egg is even fertilized, chormosomal 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 nay 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 appears 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 deviants, especially sexual deviants. 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 chromosmally 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 which may serve to explain their high level of incarceration.
Sociobiological theories fit into this focus - 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. 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. The females of any species, goes this theory, are likely to develop very different kinds of reproductive strategies given the fact they produce fewer offspring than do males. The genes of males, in competition with those of other males, include behavior that results in the greatest number of offspring. Females, who are not able to produce nearly as many offspring as are males, compete for quality, rather than quantity, behaving so as to ensure that each child produced will be likely to survive and reproduce.
Animal biologists inform us differently - some species are polyandrous, some are sexually attractive, so females actively solicit males when they are not ovulating.
A second focus of biological theories is the role of hormonal activity in shaping gender-related behaviors.
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 closed0. 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 sexually oriented to males.
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 descents, 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 is 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?
"My hormones made me do it" Not unrelated to the issue of sex differences in the brain is the question of how hormones affect the behavior of women and men.
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 eradicably male. No matter how hard people worked at making her female, her brain knew otherwise. 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?
Testosterone and Gender - One explanation for sex differences in aggression centers on the fact that males secrete higher levels of the hormone testosterone. 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. High testosterone makes a person more competitive. But recent research shows that testosterone levels rise and fall in response to competitive challenges. High before the match, goes down as the match is being play and then rises dramatically in players who win, but drops just as dramatically in those who lose.
Therefore the importance aspect may be the relationship between dominance/eminence and testosterone.
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.
Two problems - research uses the brains of animals not humans. Second problem is that the human brain changes as people age and I 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.
A third relate 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, whereas 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.
Related to this finding that 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.
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 -
Renzetti and Curran say " we may only speculate on the motives that underlie some scientists' tenacious attempts to establish a biological basis for behavioral and personality differences between women and men. The existence of difference, even if biologically caused, does not imply a hierarchical ordering, nor does it imply that one behavior or trait is inherently superior to another. "
Judith Lorber "Believing is Seeing"
We believe first, then find (see) data that fits our belief.
The reliance on only two sex and gender categories in the biological and social sciences is as epistemologically spurious as the reliance on chromosomal or genital tests to group athletes. Most research designs do not investigate whether physical skills or physical abilities are really more or less common in women and men. They start out with two social categories (women, men), assume they are biologically different (female, male), look for similarities among them and differences between them, and attribute what they have found for the social categories to sex differences. These designs rarely question the categorization of their subjects into two and only two groups, even though they often find more significant within-group differences than between-group differences.
It might be more useful in gender studies to group patterns of behavior and only then look for identifying markers of the people likely to enact such behaviors.
Lorber uses sports to illustrate her concept. She talks about gymnastics, swimming and skating being the, type of sports and the interpretation of that sport, ie, eleves, mermaids and ice queens that women have been allowed to participate in. The emphasis of women's sports have been grace and appearance not power.
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