The Abstract from 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. There is no indication that social environment after birth has an effect on gender identity or sexual orientation."
And the Abstract from Biased-Interaction Theory of Psychosexual Development: “How Does One Know if One is Male or Female?” M.Diamond Sex Roles (2006) 55:589–600
"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."
OK, to summarise: hormonal environment dictates the brain's organisation. This leads to detectable sex differences in senses of smell, hearing, emotional response, from birth. It also leads the brain to develop in particular ways later.
Sex Identity crystallises as the result if conscious and unconscious pattern-matching with others' behaviour. Appearance, dress etc seem to play a minor role if any.
The Abstract from 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. There is no indication that social environment after birth has an effect on gender identity or sexual orientation."
And the Abstract from Biased-Interaction Theory of Psychosexual Development: “How Does One Know if One is Male or Female?” M.Diamond Sex Roles (2006) 55:589–600
"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."
OK, to summarise: hormonal environment dictates the brain's organisation. This leads to detectable sex differences in senses of smell, hearing, emotional response, from birth. It also leads the brain to develop in particular ways later.
Sex Identity crystallises as the result if conscious and unconscious pattern-matching with others' behaviour. Appearance, dress etc seem to play a minor role if any.