How Many Weeks To Find Out The Gender

Biological Theories of Gender

By Dr. Saul McLeod, published 2014

People often get confused between the terms sex and gender. Sexual practice refers to biological differences between males and females. For example, chromosomes (female XX, male XY), reproductive organs (ovaries, testes), hormones (oestrogen, testosterone).

Gender refers to the cultural differences expected (by order / civilization) of men and women according to their sexual practice. A person'southward sex does non change from nativity, but their gender tin can.

In the past people tend to have very clear ideas about what was appropriate to each sex activity and anyone behaving differently was regarded as deviant.

Today nosotros accept a lot more variety and see gender as a continuum (i.e. scale) rather than two categories. Then men are complimentary to show their "feminine side" and women are free to show their "masculine traits".

The biological approach suggests there is no distinction betwixt sex & gender, thus biological sex creates gendered behavior. Gender is determined by ii biological factors: hormones and chromosomes.

Hormones

Hormones are chemic substances secreted by glands throughout the body and carried in the bloodstream. The aforementioned sex hormones occur in both men and women, but differ in amounts and in the effect that they take upon different parts of the trunk.

Testosterone is a sex hormone, which is more nowadays in males than females, and affects development and beliefs both before and afterwards nascency.

Testosterone, when released in the womb, causes the development of male person sex organs (at 7 weeks) and acts upon the hypothalamus which results in the masculinization of the brain.

Testosterone can cause typically male behaviors such as aggression, competitiveness, Visuospatial abilities, higher sexual drive etc. An surface area of the hypothalamus at the base of operations of the brain called the sexually dimorphic nucleus is much larger in male person than in females.

At the same time testosterone acts on the developing brain. The brain is divided into two hemispheres, left and right. In all humans the left side of the brain is more specialised for language skills and the right for not-verbal and spatial skills.

Shaywitz et al (1995) used MRI scans to examine brain whilst men and women carried out language tasks and found that women used both hemispheres, left only used by men.

Information technology appears that in males encephalon hemispheres piece of work more than independently than in females, and testosterone influences this brain lateralization.

Empirical Evidence

The furnishings of testosterone have been confirmed in animal studies.

Quadango et al. (1977) institute that female monkeys who were deliberately exposed to testosterone during prenatal development later engaged in more than crude and tumble play than other females.

Immature (1966) changed the sexual behavior of both male and female rats by manipulating the corporeality of male person and female hormones that the rats received during their early development.

rats after being injected with testosterone

They displayed "reversed" sexual behavior and the effects were unchangeable. A number of not-reproductive behaviors in rats are also effected by testosterone exposure around birth. These included exploratory beliefs, assailment and play.

Young believed that the exposure had changed the sexually dimorphic nucleus (SDN) in the brain, as male rats had a larger SDN than females. The results have proven to be highly replicable.

Critical Evaluation

Because this report was conducted in a lab it has depression ecological validity. For example, in the lab hormones are injected in 1 single loftier dose. Whereas in real life, hormones tend to be released by the body in pulses, in a graduated fashion. Therefore, the results might non be generalizable outside of the lab, to a more naturalistic setting.

This written report also raises the issue of whether it'due south morally and/or scientifically right to use animals in research.

Ultimately psychologists must ask themselves whether in their inquiry the ends justify the means. Past this we hateful that all inquiry using human or non-man animals must be considered in terms of the value of the results when compared to the cost (both moral and financial) of carrying out the work. The master benchmark is that benefits must outweigh costs. But benefits are nigh always to humans and costs to animals.

We should be cautious when extrapolating the results of creature inquiry to a human being population. This is because the physiologies (eastward.chiliad. brains) of humans and animals species are not identical. Also, the social and cultural variables within a man population are more complex when compared to social interactions between rats.

The consequence of this means the external validity of the research is uncertain. Notwithstanding, a study by Hines (1982) suggests it might be possible to generalize the results to humans.

Hines (1982) studied female babies born to mothers who had been given injections of male hormones during pregnancy to prevent miscarriage. They were found to exist more ambitious than normal female children. Hines concluded that the extra testosterone in the womb had affected later behavior.

Chromosomes

The normal homo trunk contains 23 pairs of chromosomes. A chromosome is a long sparse structure containing thousands of genes, which are biochemical units of heredity and govern the evolution of every man.

Each pair of chromosomes controls different aspects of development, and biological sexual activity is adamant by the 23rd chromosome pair. Chromosomes physically resemble the letters 10 and Y.

Males = XY
Females = Twenty

23 Pairs of Chromosomes of the human body

SRY Gene (Sex-determining Region Y gene)

At most 6 weeks, the SRY gene on the Y chromosome causes the gonads (sex activity organs) of the embryo to develop as testes.

embryo

If the embryo has no Y chromosome, it volition not take the SRY gene, without the SRY gene, the gonads volition develop as ovaries.

Sometimes the SRY factor is missing from the Y chromosome, or doesn't activate. The foetus grows, is born, and lives as a little girl, and later as a woman, but her chromosomes are XY. Such people are, usually, clearly women to themselves and anybody else.

Koopman et al. (1991) found that mice that were genetically female developed into male person mice if the SRY gene was implanted.

Ane of the most controversial uses of this discovery was as a ways for gender verification at the Olympic Games, under a system implemented past the International Olympic Committee in 1992. Athletes with a SRY gene were not permitted to participate every bit females.

Singular Chromosomes

Individuals with singular chromosomes develop differently than individuals with typical chromosomes - socially, physically and cognitively.

Studying people with Turner'due south syndrome and Klinefelter'south syndrome might help our understanding of gender because by studying people with atypical sexual practice chromosomes and comparison their development with that of people with typical sex chromosomes, psychologists are able to constitute which types of behavior are genetic (eastward.k. determined by chromosomes).

Turner's Syndrome

Turner'due south syndrome (XO) occurs when females develop with only one X chromosome on chromosome 23 (1 in 5000 take a chance).

Turner's syndrome

The absenteeism of the second X chromosome results in a child with a female external appearance only whose ovaries have failed to develop.

The concrete characteristics of individuals with Turner'south syndrome include lack of maturation at puberty and webbing of the neck.

In addition to concrete differences, there are differences in cerebral skills and behavior compared with typical chromosome patterns.

The afflicted individuals have higher than average verbal power only lower than average spatial ability, visual memory and mathematical skills. They besides have difficulty in social aligning at school and generally have poor relationships with their peers.

Klinefelter's Syndrome

Klinefelter's syndrome (XXY) affects i in every 750 males. In improver to having a Y chromosome, these men also have an additional X on the 23rd chromosome, leading to the arrangement XXY.

Klinefelter's syndrome

Physically they announced male, though the effect of the additional X chromosome causes less torso hair and under-developed genitals. The syndrome becomes noticeable in childhood, as the boy has poor language skills. At three years of age, the child may even so non talk. At school, their poor language skills touch on reading ability.

When they are babies, their temperament is described as passive and branch. This calmness and shyness remains with them throughout their lives.

This suggests that level of aggression have a biological rather than environmental component.

Evolutionary Explanations of Gender

Equally the evolutionary arroyo is a biological one, it suggests that aspects of homo beliefs have been coded by our genes considering they were or are adaptive.

A central claim of evolutionary psychology is that the brain (and therefore the mind) evolved to solve bug encountered by our hunter-gatherer ancestors during the upper Pleistocene catamenia over ten,000 years ago.

The evolutionary arroyo argues that gender office division appears equally an adaptation to the challenges faced by the ancestral humans in the EEA (the surroundings of evolutionary accommodation).

the environment of evolutionary adaptation

The mind is therefore equipped with 'instincts' that enabled our ancestors to survive and reproduce.

The ii sexes developed different strategies to ensure their survival and reproductive success. This explains why men and women differ psychologically: They tend to occupy unlike social roles.

To support the evolutionary perspective, the division of labour was shown to be an advantage. x,000 years ago there was division of labour between males and females. Men were the hunter gathers, breadwinners, while the mother was at dwelling house acting as the 'angel of the house' and looking after the children.

Hunting for food required speed, agility, good visual perception. And so men developed this skill.

If a women was to hunt, this would reduce the group'southward reproductive success, equally the woman was the one who was significant or producing milk. Although, the women could contribute to the important business of growing food, making clothing and shelter and so on.

This enhances reproductive success but it also important in avoiding starvation – an additional adaptive advantage.

Critical Evaluation

Deterministic approach which implies that men and women have little pick or control over their behaviors: women are natural 'nurturers' and men are naturally aggressive and competitive.

The consequence are that in modern society equal opportunities policies are doomed to neglect as men are 'naturally' more competitive, risk taking and likely to progress up the career ladder.

Biosocial Approach to Gender

The biosocial approach (Money & Ehrhardt, 1972) is an interactionist approach where by nature and nurture both play a role in gender development.

John Coin's (1972) theory was that once a biological male person or female is born, social labeling and differential handling of boys and girls collaborate with biological factors to steer development. This theory was an try to integrate the influences of nature and nurture.

Gender role preferences determined by a series of critical events:

Prenatal: exposure to hormones on the womb (determined by chromosomes). It states that biology caused by genetics, XY for a boy and XX for a girl volition give them a physical sex.

Postnatal: Parents and others label and react towards a child on the basis of his or her genitals.

Parents and other people characterization and begin to react to the child based on his or her genitals. It is when their sex has been labelled through external genitals, they gender development will begin.
The social labeling of a baby as a male child or girl leads to different treatment which produce the child\south sense of gender identity.
Western Societies view gender as having two categories, masculine and feminine, and encounter human and women every bit different species.

The way they are treated socially in combination with their biological sex volition make up one's mind the child's gender.

The approach assumes that gender identity is neutral earlier the age of iii, and can exist inverse, e.thousand. a biological male child raised as a girl will develop the gender identity of a girl. This is known as the theory of neutrality.

Empirical Testify

Rubin et al, 1974, interviewed 30 parents and asked them to use adjective pairs to describe their babies. Although at that place were no measurable differences in size betwixt the babies, parents consistently described boy babies equally better coordinated, stronger and more warning than daughters. This shows that parents label their babies.

APA Fashion References

Feder, H. H., Phoenix, C. H., & Immature, Due west. C. (1966). Suppression of feminine behavior by administration of testosterone propionate to neonatal rats. Journal of Endocrinology, 34(1), 131-132.

Hines, M. (1982). Prenatal gonadal hormones and sex differences in man behavior. Psychological Bulletin, 92(1), 56.

Koopman, P., Gubbay, J., Vivian, Northward., Goodfellow, P., & Lovell-Bluecoat, R. (1991). Male development of chromosomally female mice transgenic for Sry. Nature, 351(6322), 117-121.

Money, J., & Ehrhardt, A. A. (1972). Man and woman, boy and girl: Differentiation and dimorphism of gender identity from conception to maturity.

Quadagno, D. M., Briscoe, R., & Quadagno, J. Due south. (1977). Event of perinatal gonadal hormones on selected nonsexual behavior patterns: a critical assessment of the nonhuman and man literature. Psychological Bulletin, 84(1), 62.

Shaywitz, B. A., Shaywltz, Southward. Eastward., Pugh, Chiliad. R., Constable, R. T., Skudlarski, P., Fulbright, R. K., ... & Gore, J. C. (1995). Sex differences in the functional system of the brain for linguistic communication.

How to reference this article:

McLeod, S. A. (2014, Dec 14). Biological theories of gender. Simply Psychology. www.simplypsychology.org/gender-biology.html

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