BIOLOGY OF GENDER

The 'biology of gender' is scientific analysis of the physical basis for behavioural differences between men and women. It is more specific than sexual dimorphism, which covers physical and behavioural differences between males and females of any sexually reproducing species, or sexual differentiation, where physical and behavioural differences between men and women are described.
Biological research of gender has explored such areas as: intersex physicalities, gender identity, gender roles and sexual preference. Late twentieth century study focussed on hormonal aspects of the biology of gender. With the successful mapping of the human genome, early twenty-first century research started making progress in understanding the effects of gene regulation on the human brain.

Contents

History

Differences

Brain

Aptitude

Behavior

Nature or nurture

Motives and ethics

Research motives

Patriarchy

Ethics

See also

References

External links

Literature

Journals

History

It has long been known that there are correlations between the biological sex of animals and their behaviour.^{[1] [2] [3]} It has also long been known that human behaviour is influenced by the brain.

The late twentieth century saw an explosion in technology capable of aiding sex research. John Money and Milton Diamond made great progress towards understanding the formation of gender identity in humans. Extensive advances were also made in understanding sexual dimorphism in other animals. For example, there were studies on the effects of sex hormones on rats. The early twenty first century started producing even more amazing results concerning genetically programmed sexual dimorphism in rat brains, prior even to the influence of hormones on development. "Genes on the sex chromosomes can directly influence sexual dimorphism in cognition and behaviour, independent of the action of sex steroids."^[4]

Differences

Brain

The brains of many animals, including humans, are significantly different for males and females of the species.^[5] Both genes and hormones affect the formation of many animal brains before "birth" (or hatching), and also behaviour of adult individuals. Hormones significantly affect human brain formation, and also brain development at puberty. Both kinds of brain difference affect male and female behaviour.

In 2006, Alexandra M. Lopes and others published that:
Although men have a larger brain size, even when adjusted for body mass, there is no definite indication that men are more intelligent than women. In contrast, women have a higher density of neurons in certain parts of the brain. However, difference is seen in the ability to perform certain tasks. On average women are superior on various measures of verbal ability, while men have specific abilities on measures of mathematical and spatial ability.
Richard J. Haier and colleagues at the universities of New Mexico and California (Irvine) found, using brain mapping, that men have more than six times the amount of gray matter related to general intelligence than women, and women have nearly ten times the amount of white matter related to intelligence than men (Haier, Rex E Jung and others, 'Structural Brain Variation and General Intelligence', ''NeuroImage'' '23' (2004): 425–433). "These findings suggest that human evolution has created two different types of brains designed for equally intelligent behavior," according to Haier. Gray matter is used for information processing, while white matter consists of the connections between processing centers.
Although the Haier study is valid, the specific quotation above is probably biased, since it fails to take into account fact that brains develop around social need, and most modern societies encourage particular types of thought in correspondence with particular gender roles.

Aptitude

A 2001 report by Richard J. Coley of the ETS found that females often outperformed males on various measures of verbal ability, while males tended to outperform females on measures of mathematical and spatial ability. [1]
Studies have shown that men show a greater ''variance'' in scores than females. The average scores of young men and women in mathematics, for example, will be close, but there will be more men than women in the very low scores and in the very high scores. In this sense, the red bell curve in the diagram represents women, compared to men in green.^[6] There is evidence to suggest that forms of autism may be essentially extreme expressions of certain typically male characteristics.^[7] [8] This is represented by the blue in the diagram.

Behavior

Hormones have been linked with male aggression.^[9]

For an illustrated description of clear differences between male and female brain response to pain see Laura Stanton and Brenna Maloney, 'The Perception of Pain', ''Washington Post'', 19 December 2006.

Nature or nurture

There is a lot of variation in men and women that is not yet understood. It cannot be ''proven'' that male-ness or female-ness is 100% biological (in fact virtually all studies show that it is not). However, it is also probably true that male-ness and female-ness are not 100% determined by upbringing and culture (social determinism). These issues remain an area of ongoing research, with profound relevance for people of many different types. One journal (Genes, Brains and Behavior) is devoted specifically to research in this area.

Motives and ethics

Research motives

Most biological research is motivated by seeking the causes of diseases in human beings, and ways of treating or preventing those diseases. For example, there is study into genetic predisposition to, or causes of, Alzheimer's disease and mental illnesses. Also:
^[10]

Patriarchy

Most societies, particularly those influenced by Western norms, have been patriarchal.^[11] Some people believe things like patriarchy and sexism are not only inevitable but constructive.^[12][13] However, many others consider them destructive and want to eliminate them.^[14][15]

Ethics

Even if it was possible to remove partriarchal behaviour by an injection, there are ethical questions that need answers before any such procedure could be performed:

★ Should it be made law for such an injection to be given?

★ Should parents be given the choice, or only mothers?

See also

★ Brain Sex, the book

★ Platypus (complex sex chromosomes)

★ Prenatal hormones and sexual orientation

References

1. Charles Darwin, ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life'', (London: John Murray, 1859).
2. Charles Darwin, ''The Descent of Man, and Selection in Relation to Sex'', 2 volumes, (London: John Murray, 1871).
3. Helena Cronin, ''The Ant and the Peacock: Altruism and Sexual Selection from Darwin to Today'', (Cambridge: Cambridge University Press, 1991).
4. Sexual dimorphism in cognition and behaviour: the role of
X-linked genes, , David H, Skuse, European Journal of Endocrinology,
5. Robert W Goy and Bruce S McEwen. ''Sexual Differentiation of the Brain: Based on a Work Session of the Neurosciences Research Program''. MIT Press Classics. Boston: MIT Press, 1980.
6. Camilla Persson Benbow and Julian C Stanley, 'Sex Differences in Mathematical Reasoning Ability: More Facts', ''Science'' 222 (1983): 1029-1031.
7.
Simon Baron-Cohen,
'The Extreme-Male-Brain Theory of Autism',
in H Tager-Flusberg (ed.), ''Neurodevelopmental Disorders'', (Boston: The MIT Press, 1999).
8. Simon Baron-Cohen. ''Mindblindness: An Essay on Autism and Theory of Mind''. (Boston: The MIT Press, 1997).
9. Elizabeth J. Susman, Gale Inoff-Germain, Editha D. Nottelmann, and others, 'Hormones, Emotional Dispositions, and Aggressive Attributes in Young Adolescents', ''Child Development'' 58 (1987): 1114-1134.
10. Key Step in Gene Activation Discovered, , Barbara K, Kennedy, Science Journal,
11. Patriarchy (anthropology)
12. Steven Goldberg, ''Why Men Rule''
13. Moir and Jessel, ''Brain Sex''
14. Pierre Bourdieu, 'On Male Domination', ''Le Monde Diplomatique'' English edition (October 1998).
15. Patriarchy in feminism

External links

★ International Behavioural and Neural Genetics Society

★ Kritz, Francesca Lunzer. 'Not Feeling Each Other's Pain: Men and Women Hurt Differently – and Some of The Difference May Really Be in Their Heads'. ''The Washington Post'', 19 December 2006. Page HE01.

★ Marks, Jonathan. 'Essay 8: Primate Behavior'. In ''The Un-Textbook of Biological Anthropology''. Unpublished, 2007.

★ Pinker vs. Spelke. 'The Science of Gender and Science'. ''Edge'' (The Third Culture) 16 May, 2005. (multimedia record of public debate)

★ Rabinowicz T, and others. 'Gender differences in the human cerebral cortex: more neurons in males; more processes in females'. ''Journal of Child Neurology'' '14' (1999): 98-107.

★ Runyan, Andrea. 'Sex Is More Than Socialization'. ''epowiki'', August 18, 2005.

★ Shaywitz, BA, and others. 'Sex differences in the functional organisation of the brain for language'. ''Nature'' '373' (1995): 607-609.

Literature

★ Baron-Cohen, Simon. ''The Essential Difference: The Truth about the Male and Female Brain''. New York: Perseus Books Group, 2003.

★ Brizendine, Louann. ''The Female Brain''. New York: Morgan Road Books, 2006.

★ Brown, Donald E. ''Human Universals''. New York: McGraw Hill, 1991.

★ Kimura, Doreen. ''Sex and Cognition''. MIT Press, 1999.

★ Moir, Anne and David Jessel. ''Brain Sex: The Real Difference Between Men and Women''.

★ Pinker, Steven. ''The Blank Slate: A Modern Denial of Human Nature''. London: Penguin Books, 2002.

Journals

★ ''Genes, Brains and Behavior''