Biological influences on gender and transgender

Gender is a social construct into which feed biological and social factors like:

1.      DNA which may be normal: or not normal. See DSD: disorders of sex development. University of Michigan Health System

2.     Sexual differentiation: check out embryology of mammals, in particular humans. Sexual Differentiation

3.     Visible external genitalia and the invisible internal sex organs which may be different again: e.g. Some people are born with testes and ovaries. And this is different from the DNA sex. University of Michigan Health System

4.     Gestational chemistry: was the female infant bathed in testosterone which is thought to stimulate masculinity in behaviour or, alternatively the male infant getting too much of female hormones while developing. These situations occur because of drugs, drinking contaminated water, medication and a host of other reasons. The outcomes are children who feel and behave as if they are the opposite gender without there being any perceived hard biological connection. Normal Sexual Dimorphism of the Adult Human Brain Assessed by In Vivo Magnetic Resonance Imaging   

       Prenatal_hormones_and_sexual_orientation

5.     Socialisation: parents and doctors and family and ultimately society select gender for the infant, unfortunately frequently underlining the option with surgery. So the individual is told they are a boy or girl and socially expected to behave as that particular sex, whether they feel like it or not.

6.     Puberty: This is a crucial time for people with uncertain sexual orientation and vague or chosen gender. Their body changes in ways unanticipated which may force an alteration of the persons gender identity. Select Population of Females turn into Males during Puberty, Growing Male Genitalia

7.     Personal ideation: who does the person think they are? I know men who went through andropause and, because suddenly they felt emotions and cried at movies, they have decided that he must now become a she. Because, despite having lived as a man for 50+ years, he's not feeling like a man anymore so he believes that the only option open to him (so he can accept himself) is to become a female. Andropause/Male Menopause It is of no use pointing out that as a genetic male, if one is feeling this way, therefore he is having a genuinely masculine experience, no. It is unacceptable to be an emotional, tearful, feminine man. Only women think and feel these ways. This is from actual conversations I have had with men transitioning to women at an average age of 63. 81-year-old woman becomes oldest person to have gender reassignment surgery

8.     The transgender person may vary markedly from their biological DNA profile, or may have changed gender in order to try to match their DNA.

9.     I have selected only a tiny sampling of the information available to the scholar seeking understanding of the phenomenon of transgender and how it relates to the biology and physiology of the human being.

10.  My analysis is: that there are in fact so very many influences and variables, chemical, inherited, biological and social, influencing how sex and gender are arrived at in any individual, that it is remarkable that we recognise only two sexual varieties, instead of many.

11.   I recommend that you read any books by Dr John Money PHd. It was he who chose gender as the word to which we now attach all these multifarious sex-related issues and explained the fundamental issues.