Androgen insensitivity syndrome is a condition that affects sexual development before birth and during puberty. People with this condition are genetically male, with one X chromosome and one Y chromosome in each cell. Because their bodies are unable to respond to certain male sex hormones (called androgens), they may have mostly female external sex characteristics or signs of both male and female sexual development.

Complete androgen insensitivity syndrome occurs when the body cannot use androgens at all. People with this form of the condition have the external sex characteristics of females, but do not have a uterus and therefore do not menstruate and are unable to conceive a child (infertile). They are typically raised as females and have a female gender identity. Affected individuals have male internal sex organs (testes) that are undescended, which means they are abnormally located in the pelvis or abdomen. Undescended testes have a small chance of becoming cancerous later in life if they are not surgically removed. People with complete androgen insensitivity syndrome also have sparse or absent hair in the pubic area and under the arms.

The partial and mild forms of androgen insensitivity syndrome result when the body's tissues are partially sensitive to the effects of androgens. People with partial androgen insensitivity (also called Reifenstein syndrome) can have genitalia that look typically female, genitalia that have both male and female characteristics, or genitalia that look typically male. They may be raised as males or as females and may have a male or a female gender identity. People with mild androgen insensitivity are born with male sex characteristics, but they are often infertile and tend to experience breast enlargement at puberty.



Mutations in the AR gene cause androgen insensitivity syndrome. This gene provides instructions for making a protein called an androgen receptor. Androgen receptors allow cells to respond to androgens, which are hormones (such as testosterone) that direct male sexual development. Androgens and androgen receptors also have other important functions in both males and females, such as regulating hair growth and sex drive. Mutations in the AR gene prevent androgen receptors from working properly, which makes cells less responsive to androgens or prevents cells from using these hormones at all. Depending on the level of androgen insensitivity, an affected person's sex characteristics can vary from mostly female to mostly male.



Complete androgen insensitivity syndrome affects 2 to 5 per 100,000 people who are genetically male. Partial androgen insensitivity is thought to be at least as common as complete androgen insensitivity. Mild androgen insensitivity is much less common.



This condition is inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. In genetic males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In genetic females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Males are affected by X-linked recessive disorders much more frequently than females.

About two-thirds of all cases of androgen insensitivity syndrome are inherited from mothers who carry an altered copy of the AR gene on one of their two X chromosomes. The remaining cases result from a new mutation that can occur in the mother's egg cell before the child is conceived or during early fetal development.

Wonderful Blog, Thing's That We Generally Do Not Get To Know About, As Well As Being Informative, - Good Stuff !

Thank's Rosy, even one comment makes it worthwhile, Because of my childhood, I have always had this ''told you so'' attitude, if people are interested, I have done vast amounts of research into varying trans clinical issues, even to male female brains, which can develop as a result of AIS

Just Got My D.N.A Chromosome Test Back After My Trip To Thailand, It Seem's I Was Told Wrong All Those Year's Ago ! I Am XY But With No Controlling X Or Y As It Is Even Across The Board, So What Doe's That Make Me ?

CNS Brain male feminisation

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,





Cristine:- So is it safe to say the percentage difference between the number of neurons BSTMP M to F and F to male affect the degree of GID and could possible it

result in dual gender identity when more or less balanced? with no predominate influence.

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



The fetal brain develops during the intrauterine period in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge. In this way, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation are programmed or organized into our brain structures when we are still in the womb. However, since sexual differentiation of the genitals takes place in the first two months of pregnancy and sexual differentiation of the brain starts in the second half of pregnancy, these two processes can be influenced independently, which may result in extreme cases in trans-sexuality. This also means that in the event of ambiguous sex at birth, the degree of masculinization of the genitals may not reflect the degree of masculinization of the brain. in fact in the examination of male to female transexuals the brain composition would suggest varying degrees uf under masculisation vegring on the near total feminisation. There is no indication that social environment after birth has an effect on gender identity or sexual orientation

Regional gray matter variation in male-to-female transsexualism. by Luders et al Neuroimage. 2009 Jul 15;46(4):904-7.
We analyzed MRI data of 24 male-to-female (MTF) transsexuals not yet treated with cross-sex hormones in order to determine whether gray matter volumes in MTF transsexuals more closely resemble people who share their biological sex (30 control men), or people who share their gender identity (30 control women). Results revealed that regional gray matter variation in MTF transsexuals is more similar to the pattern found in men than in women. However, MTF transsexuals show a significantly larger volume of regional gray matter in the right putamen compared to men. These findings provide new evidence that transsexualism is associated with distinct cerebral pattern, which supports the assumption that brain anatomy plays a role in gender identity

The scientific literature has already come to a consensus on the existence of cognitive sex differences, especially with regard to spatial ability. Both neural/hormonal and social factors contribute to those differences. See Diane Halpern's "Sex Differences in Cognitive Abilities".

Stereotypes, including gender stereotypes, are mostly accurate. So saying that some view or conclusion is a gender stereotype is not a real criticism. See Lee Jussim's "Social Perception and Social Reality: Why Accuracy Dominates Bias and Self-Fulfilling Prophecy".

Finally, let's assume the real reason why women have bigger corpus callosums is that they have smaller brains. Does the relation between sex and corpus callosum size cease to exist? No. Women on average will still have larger corpus callosums and all the (presumed) behavioural/cognitive characteristics associated with it.



If you look at the sexual dimorphism from an evolutionary perspective, this makes perfect sense. In early human societies, men went out to hunt while women stayed in the village (with very few exceptions).

The traits that made men more successful were those that allowed them to be better hunters and warriors: so coordinated action, perception of environmental opportunities and dangers. For the women in the village, their success is more dependent on "politics" and relationships. Instead of organizing hunts, the successful woman is one who is well liked by people and use strong communication skills and wits to solve problems (and not braun since they will lose to the stronger males).

Thus over time, as the traits that marks a successful man and woman differs, it makes sense that there should be sexual dimorphism in brain structures.



Which in turn is a probable and logical cause for some brain structure difference in male to female transexuals.


genetic female brains are different to genetic male brains. Some parts of a male brain is larger than a females and some parts of a females brains are larger than the males. Its been shown through MRI scans that some transexual male to female brains have some of the characteristics of the natal female brain. The androgen receptors in the brain regulate the formation of the brain during the early stages of pregnancy, if the androgen receptor is not working properly then it can result in slight or major diferences in a male to to female transexual brain, perhaps causing those people to think more like a woman.
Thinking logically, if the differences were balanced, I suppose, yes it could lead to a dual gender identity.

But this might not be the only answer, I had a brain scan, and the subject differences were considered to small to be of any major significance, inconclusive. But there again I was born with Reifensteins syndrome, AIS, androgen insensativity syndrome, so although it affected my physical appearance, it was concluded that it had no major impact on how my brain was constructed.

44. In sum, gender identity, whether consistent or inconsistent with other sex characteristics, may be understood to be “much less a matter of choice and much more a matter of biology” (Coolidge et al., 2000). The scientific evidence supports the paradigm that transsexualism is strongly associated with the neurodevelopment of the brain (Zhou et al., 1995; Kruijver et al., 2000). It is clear that the condition cannot necessarily be overcome by “consistent psychological socialisation as male or female from very early childhood” and it is not responsive to psychological or psychiatric treatments alone (Green, 1999). It is understood that during the fetal period the brain is potentially subject to the organising properties of sex hormones (Kruijver et al., 2000; 2001; 2002; 2003). In the case of transsexualism, these effects appear to be atypical, resulting in sex-reversal in the structure of the BSTc, and possibly other, as yet unidentified, loci (Kruijver, 2004). The etiological pathways leading to this inconsistent development almost certainly vary from individual to individual, so no single route is likely to be identified. Different genetic, hormonal and environmental factors, acting separately or in combination with each other, are likely to be involved in influencing the development of the psychological identification as male or female. Psychosocial factors and cultural mores are likely to impact on outcomes (Connolly, 2003).
Gender Differences in Human Brain: A Review Z.F Zaidi The Open Anatomy Journal, 2010, 2, 37-55
CONCLUSION The male and the female brains show anatomical, functional and biochemical differences in all stages of life. These differences begin early during development due to a combination of genetic and hormonal events and continue throughout the lifespan of an individual

Rosy did you have an AIS test, Usually done by way of a lumber puncture (extracting samples of DNA from the spine) I had all the test done at Addenbrooks Hospital at the Gene clinic when I was 15. People with AIS are in the majority XY, either the encoding gene is mutated or the androgen receptors are unable to recognise in total or partially influencing factor . such as testosterone.