Synopsis of the Etiology of Gender

• Posted by Cristine Jennifer Shye. BL. B/acc January 28, 2018 Filed in Member's Blogs 1,778 views
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  Many transsexuals, therapists, human sexuality researchers, religious liberals, and others believe that transsexuality is determined before birth. Some believe that it is determined by one's DNA at conception. others hold to the theory that it is caused by irregular levels of sex hormones to which the fetus may be subjected. These beliefs are grounded in research into genes and traits of transsexuals.

   

  Cristine Shye
  
  Is transsexualism genetically determined? 
  
  As noted elsewhere in this thread a transsexual is a person who experiences Gender Identity Disorder (a.k.a. Gender Dysphoria), Their genetic gender is different from their perceived gender. Some describe themselves as a woman trapped in a man's body, or vice versa. 
  
  This disorder is rare. It generally causes serious personal conflicts and depression, often starting in pre-school children. Their level of frustration and anxiety is often so high that many become suicidally depressed. The rate of completed suicide for transsexuals was once believed to be about 50% by age 30. Since then, sex reassignment surgery (SRS) has become more widely accessible. Many transsexuals can now have their physical appearance modified to make them appear more like the gender that they feel they are. This surgery has been shown to be generally effective, and the suicide rate among transsexuals has apparently been greatly reduced. 
  
  Religious conservatives generally believe that transsexuality is a chosen lifestyle to which a person can become addicted. The solution is therapy and prayer. 
  
  The opinion of some gays, lesbians, and bisexuals towards the causes of transsexuality may be influenced by a desire to support their belief that sexual orientation is similarly genetically determined. 
  
  Australian DNA study during 2008: 
  
  Australian researcher Professor Vincent Harley has led an Australian-American study of transsexuality. He acknowledges that the cause(s) of transsexuality have been debated for years. He said: 
  "There is a social stigma that transsexualism is simply a lifestyle choice. However our findings support a biological basis of how gender identity develops." 
  
  He was the lead researcher in the an Australian-American genetic study of transsexuals -- the largest to date. Included were several research groups in Melbourne Australia and in the University of California in Los Angeles (UCLA). It was funded by the National Health and Medical Research Council in Australia, and the National Institutes of Health in the U.S. 
  
  They compared DNA from 112 MTF (male-to-female) transsexuals with DNA from 250 males who did not experience gender dysphoria. Results of the study were published in the 2008-OCT-27 edition of the journal Biological Psychiatry. 
  
  The researchers found that the transsexual subjects were more likely to have a longer version of the androgen receptor gene in their DNA. 
  
  Lauren Hare, a researcher at Prince Henry's Institute said: 
  
  "We think these genetic differences might reduce testosterone action and under-masculinize the brain during fetal development." 
  
  "Studies in cells show the longer version of the androgen receptor gene works less efficiently at communicating the testosterone message to cells. Based on these studies, we speculate the longer version may also work less efficiently in the brain." 
  
  Terry Reed from the Gender Identity Research and Education Society said: 
  
  "This study appears to reinforce earlier studies which have indicated that, in some trans people, there may be a genetic trigger to the development of an atypical gender identity." 
  
  "However, it may be just one of several routes and, although it seems extremely likely that a biological element will always be present in the aetiology of transsexualism, it's unlikely that developmental pathways will be the same in all individuals." 
  
  Researcher Trudy Kennedy, director of the Monash Gender Dysphoria Clinic, said the study supported previous evidence that genetics and brain gender were important in transsexuality. She said: 
  
  "This is something that people are born with and it's certainly not a lifestyle choice as some have suggested." 
  
  
  Studies of fingerprints, left handedness, and ancestry of transsexuals: 
  
  During 2000-JUL, Professor Richard Green, visiting professor of psychiatry at Imperial College in London, UK discussed transsexuality at the annual meeting of the Royal College of Psychiatrists. His presentation was based on a study of 400 male-to-female (MTF) and 100 female-to-male (FTM) transsexuals in the late 1990s at the gender identity clinic in Charing Cross Hospital in London. His group determined that: 
  
  
  Over 50% of transsexuals are left-handed -- many times that of the general population. 
  Transsexuals had distinctive styles of ridged finger prints, and 
  Transsexuals had more aunts than uncles on their mother's side. 
  Male transexuals had more older brothers than average. 

   

   1. Introduction The role of the androgen receptor in CNS masculinization or the absence of same in male feminisation 
  The medial posterior region of the bed nucleus of the stria terminalis (BSTMP) and the locus coeruleus (LC) show opposite patterns of sexual dimorphism. The BSTMP in males is greater in volume and number of neurons than in females (male N female) while in the LC, the opposite is true (female N male). To investigate the possible role of the androgen receptor (AR) in the masculinization of these two structures, males with the testicular feminization mutation (Tfm) were compared to their control littermate males. No differences were seen in the number of neurons of the BSTMP between Tfm and their control littermate males, while in the LC, Tfm males have a greater number of neurons than their control littermate males. These results show that the AR is involved in the control of neuron number in the LC but not in the BSTMP. Results based on the LC suggest that when females have a larger brain area than males, masculinization in males may be achieved through the AR, with androgens perhaps decreasing cell survival. 
  
  Sex differences in the mammalian brain have two main characteristics: they often occur in neural circuits related 
  to reproductive physiology and behavior and they are seen in two opposite morphological patterns In one 
  pattern, males have greater volumes and/or number of neurons than females (male N female), while in the other, the opposite is true (female N male) Existing evidence suggest that gonadal androgens are involved in the development of sex differences in structures that are larger in males than in females,

   

  Scientists and sociologists have argued for centuries over which influences people's personalities more: nature (genetics) or nurture (upbringing and cultural context). 
  
  Contemporary feminist theory holds that, excluding biological sex characteristics, all "masculine" or "feminine" behavior is the product of culture. In the 1980s, Candace West and Don Zimmerman coined the term "doing gender" -- acting in accordance with male or female behavioral norms. A woman who uses flirtatious mannerisms, according to this theory, is doing so not as a result of genetics, but rather because she's performing feminism to fit in with social norms -- because of her nurture. 
  
  But a recent study of male-to-female transsexuals -- people who have male genitalia but self-identify as females -- isolated a genetic peculiarity in its subjects. 
  Genetic Basis for Transsexualism 
  
  A transsexual is a person who does not identify with his or her biological sex. A male-to-female transsexual was born with male genitalia but self-identifies as a woman; a female-to-male transsexual was born with female genitalia but self-identifies as a man. 
  
  In October 2008, researchers at several universities published a study where they had compared DNA samples from 112 Australian and American male-to-female transsexuals with samples from 250 typical men. The research -- led by Vincent Harley of Prince Henry's Institute in Melbourne, Australia -- focused on three genes encoding sex hormones. One of these three, the androgen receptor gene, was longer in transsexual subjects than in non-transsexual controls. The significance? 
  
  A longer androgen receptor gene could reduce testosterone during brain development, a hormone vital for male sex characteristics and behavior. So if male-to-female transsexuals have longer androgen receptor genes, they might have less testosterone, the precursor to their female self-identification. If this biological explanation is true across the board, it argues against the possibility that transsexualism has no basis in genetics. 
  
  
  The Long View 
  
  Harley's study indicates that gender identity could have genetic roots, but it is important to keep these findings in perspective. First, the sample size -- at a little over 100 subjects -- was fairly small. Second, the study only examined three genes. And third, it would be imprudent to extrapolate from a study of a very specific subject group (male-to-female transsexuals) to make broader theorizations about gender identity without examining other populations. Similar to research on homosexuality genetics, it is not conclusive, but it does raise some interesting questions and opportunities for future research. 

  This post was edited by Cristine Shye. BL at October 5, 2014 2:08 pm BST 
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  Cristine Jennifer Shye B.acc. BL (GS Admin)