It has been claimed by biologists that the brains of females and males are different in obscure ways. However, physical differences in adults may be due to psychological and sociological pressures on the brains of each gender, because cultures and societies may exaggerate roles and stereotypes, having an impact on brain plasticity.
On top of society’s role in forming gender identity, we can see in current biological data of brains and their relation to gender identity due to “molecular and hormonal mechanisms.” (Rosario, 276-278) It has been shown that the structure of brains in Homo sapiens can take on
either a male or female form from a variety of factors during critical postnatal periods.The biology of sexual identity is revealing important data that points to diversity in sexual orientation, leading us to accept that looking at gender in a binary fashion is unacceptable; gender identity in Homo sapiens is probably much more ambiguous and diverse then we once thought. (Rosario, 276-279) From this we can conclude that the gender identity listing in the current Diagnostic and Statistical Manual of Mental Disorders should be eliminated. Genetic engineering of the brain will only increase the ambiguity if we choose. A post-binary-gender society is possible, not only in the future, but it may already be here naturally.
As it turns out neuroscience and genetics is showing how the brains of LGBT people are really ambiguous. There are more than 20 or 30 ways the brain could be "feminized" or "masculinized" or somewhere in between, in that the brains between men and women are a little different dimorphicly on a macro scale. (Rosario, 276-278) There are of course non-controversial differences between genders. In fact, I just implied one of them: that “gender” exists and is a word that describes something, but what does it describe?
Biologists have identified differences between members of the same species that can increase the likelihood of sexual reproduction, the difference in each species is known as gender or sex, which usually comes in the form of “male” and “female.” Sexual dimorphism is used to describe the phenotypical difference between males and females of the same species. An example of sexual dimorphism in gorillas is the fact that males tend to be twice the size of females. Homo sapiens however have less distinctive sexual dimorphic characteristics than many other animals. (Campell, 277)
Today in the United States we have access to vast amounts of research that has been done on sexual dimorphism, gender identity, and LGBT issues. Unfortunately many people do not know this, and still discriminate against LGBT people. Just this year California voted in favor of Prop. 8 marriage, and in the same year the American Psychiatric Association appointed Dr. Kenneth Zucker to the Sexual and Gender Identity Disorder committee of the DSM-V. This
prompted protests immediately after it was released because Dr. Zucker supports the listing and has been known to do research which helps psychiatrists to identify gender disorders in children and help parents to condition their children who are diagnosed with Gender Identity Disorder to go along with their phenotype.Geneticists are finding genes outside of the X and Y chromosomes that may play a role in gender identity. They are also finding the results of mutated nucleotide order within the X and Y chromosomes related to gender identity. There are so many possibilities for a mutation to occur from the moment of conception that many more years of science will be needed to fully understand gender identity. While the brains of males and females within humans differ slightly, these subtle differences might make all the difference when it comes to gender identity, whether the person is born with normal XX or XY, or abnormal gender chromosomes and genes.
Traditional values of looking at gender in binary fashion grow less and less important as scientists show that gender identity is diverse in nature and is caused by many biological and social conditions. If one were to look at the pure science of gender identity, it not only appears that a postgender society is possible but it seems we are already living in one.
Campbell, Neil, Jane Reece, Lwarence Mitchell and Martha Taylor. Biology: Concepts & Connections. San Francisco: Pearson Education, Inc., 2003.
Knickmeyer, Rebecca C., and Baron-Cohen. "Fetal Testosterone and Sex Differences in Typical Social Development and in Autism ." Journal of Child Neurology 25 (2005): 825-845.
Kohl, James V. 'The Mind's Eyes” Journal of Psychology & Human Sexuality,18:4, (2007): 313 — 369.
Rosario, Vernon A. “Quantum Sex: Intersex and the Molecular Deconstruction of sex. GLQ: A Journal of Lesbian and Gay Studies Vol 15 (2009): 267-284.
Spitzer, Robert L “Sexual and Gender Identity Disorders.” Journal of Psychology & Human Sexuality 17:3. (2006): 111 – 116.
This is an excerpt from a larger piece.
Yes, But….
“However physical differences in adults may be due to psychological and sociological pressures on the brains of each gender, because cultures and societies may exaggerate roles and stereotypes, having an impact on brain plasticity. “
Where’s the data? This is a plausible hypothesis, and I’d be astounded if it were not true to some degree.
But… different regions of the brain have different degrees of plasticity. Some appear invariant regardless of post-natal environment, barring gross physical trauma.
I think we must draw a distinction between the areas of “gendered behaviour” which are post-natal, and which are innate.
Recommended Reading (all available online)
Sexual Hormones and the Brain: An Essential Alliance for Sexual Identity and Sexual Orientation Garcia-Falgueras A, Swaab DF Endocr Dev. 2010;17:22-35
e.g.
“Alexander and Hines [2], who offered dolls, toy cars and balls to green Vervet monkeys found the female monkeys consistently chose the dolls and examined these ano-genitally, whereas the male monkeys were more interested in playing with the toy cars and with the ball….”
Biased-Interaction Theory of Psychosexual Development: “How Does One Know if One is Male or Female?” M. Diamond, Sex Roles (2006) 55:589:600
e.g.
“A theory of gender development is presented that incorporates early biological factors that organize predispositions in temperament and attitudes. With activation of these factors a person interacts in society and comes to identify as male or female. The predispositions establish preferences and aversions the growing child compares with those of others. All individuals compare themselves with others deciding who they are like (same) and with whom are they different. These experiences and interpretations can then be said to determine how one comes to identify as male or female, man or woman. In retrospect, one can say the person has a gendered brain since it is the brain that structures the individual’s basic personality; first with inherent tendencies then with interactions coming from experience. “
Male-to-female transsexuals show sex-atypical hypothalamus activation when smelling odorous steroids by Berglund et al Cerebral Cortex 2008 18(8):1900-1908;
Male:to:female transsexuals have female neuron numbers in a limbic nucleus. Kruiver et al J Clin Endocrinol Metab (2000) 85:2034:2041
Sexual differentiation of the human brain: relevance for gender identity, transsexualism and sexual orientation. Swaab Gynecol Endocrinol (2004) 19:301:312.
A sex difference in the human brain and its relation to transsexuality. by Zhou et al Nature (1995) 378:68:70.
A sex difference in the hypothalamic uncinate nucleus: relationship to gender identity by Garcia-Falgueras et al Brain. 2008 Dec;131(Pt 12):3132-46.
“We spoke for 2 1/2 hours on why cross gender identity was a normal inherited variation of humans. We showed how Transgender Brains think, smell, and hear like the opposite sex.”— Prof Sid Ecker, private correspondence, available at http://aebrain.blogspot.com/2009/05/brain-gender-identity-presentation-by.html