Testosterone is the primary male sex hormone and androgen in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testicles and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. It is associated with increased aggression, sex drive, dominance, courtship display, and a wide range of behavioral characteristics. In addition, testosterone in both sexes is involved in health and well-being, where it has a significant effect on overall mood, cognition, social and sexual behavior, metabolism and energy output, the cardiovascular system, and in the prevention of osteoporosis. Insufficient levels of testosterone in men may lead to abnormalities including frailty, accumulation of adipose fat tissue within the body, anxiety and depression, sexual performance issues, and bone loss.
The relationship between biology and sexual orientation is a subject of on-going research. While scientists do not know the exact cause of sexual orientation, they theorize that it is caused by a complex interplay of genetic, hormonal, and environmental influences. However, evidence is weak for hypotheses that the post-natal social environment impacts sexual orientation, especially for males.
Sex differences in psychology are differences in the mental functions and behaviors of the sexes and are due to a complex interplay of biological, developmental, and cultural factors. Differences have been found in a variety of fields such as mental health, cognitive abilities, personality, emotion, sexuality, friendship, and tendency towards aggression. Such variation may be innate, learned, or both. Modern research attempts to distinguish between these causes and to analyze any ethical concerns raised. Since behavior is a result of interactions between nature and nurture, researchers are interested in investigating how biology and environment interact to produce such differences, although this is often not possible.
The empathising–systemising (E–S) theory is a theory on the psychological basis of autism and male–female neurological differences originally put forward by English clinical psychologist Simon Baron-Cohen. It classifies individuals based on abilities in empathic thinking (E) and systematic thinking (S). It measures skills using an Empathy Quotient (EQ) and Systemising Quotient (SQ) and attempts to explain the social and communication symptoms in autism spectrum disorders as deficits and delays in empathy combined with intact or superior systemising.
Childhood gender nonconformity (CGN) is a phenomenon in which prepubescent children do not conform to expected gender-related sociological or psychological patterns, or identify with the opposite sex/gender. Typical behavior among those who exhibit the phenomenon includes but is not limited to a propensity to cross-dress, refusal to take part in activities conventionally thought suitable for the gender and the exclusive choice of play-mates of the opposite sex.
The Female Brain is a book written by the American neuropsychiatrist Louann Brizendine in 2006. The main thesis of the book is that women's behavior is different from that of men due, in large measure, to hormonal differences. Brizendine says that the human female brain is affected by the following hormones: estrogen, progesterone, testosterone, oxytocin, neurotransmitters, and that there are differences in the architecture of the brain that regulate such hormones and neurotransmitters.
Sexual differentiation in humans is the process of development of sex differences in humans. It is defined as the development of phenotypic structures consequent to the action of hormones produced following gonadal determination. Sexual differentiation includes development of different genitalia and the internal genital tracts and body hair plays a role in sex identification.
In Jewish tradition, the term androgynos refers to someone who possesses both male and female sexual characteristics. Due to the ambiguous nature of the individual's sex, Rabbinic literature discusses the gender of the individual and the legal ramifications that result based on potential gender classifications. In traditionally observant Judaism, gender plays a central role in legal obligations.
Cordelia Fine is a Canadian-born British philosopher of science, psychologist, and writer. She is a full professor in the History and Philosophy of Science programme at the University of Melbourne, Australia. Fine has written three popular science books on the topics of social cognition, neuroscience, and the popular myths of sex differences. Her latest book, Testosterone Rex, won the Royal Society Science Book Prize, 2017. She has authored several academic book chapters and numerous academic publications. Fine is also noted for coining the term 'neurosexism'.
Delusions of Gender: How Our Minds, Society, and Neurosexism Create Difference is a 2010 book by Cordelia Fine, written to debunk the idea that men and women are hardwired with different interests. The author criticizes claimed evidence of the existence of innate biological differences between men and women's minds as being faulty and exaggerated, and while taking a position of agnosticism with respect to inherent differences relating to interest/skill in "understanding the world" versus "understanding people", reviews literature demonstrating how cultural and societal beliefs contribute to sex differences.
The hormonal theory of sexuality holds that, just as exposure to certain hormones plays a role in fetal sex differentiation, such exposure also influences the sexual orientation that emerges later in the individual. Prenatal hormones may be seen as the primary determinant of adult sexual orientation, or a co-factor with genes, biological factors and/or environmental and social conditions.
Leydig cell hypoplasia (LCH), also known as Leydig cell agenesis, is a rare autosomal recessive genetic and endocrine syndrome affecting an estimated 1 in 1,000,000 genetic males. It is characterized by an inability of the body to respond to luteinizing hormone (LH), a gonadotropin which is normally responsible for signaling Leydig cells of the testicles to produce testosterone and other androgen sex hormones. The condition manifests itself as pseudohermaphroditism, hypergonadotropic hypogonadism, reduced or absent puberty, and infertility.
Transgender hormone therapy, also called hormone replacement therapy (HRT) or gender-affirming hormone therapy (GAHT), is a form of hormone therapy in which sex hormones and other hormonal medications are administered to transgender or gender nonconforming individuals for the purpose of more closely aligning their secondary sexual characteristics with their gender identity. This form of hormone therapy is given as one of two types, based on whether the goal of treatment is masculinization or feminization:
Rebecca M. Jordan-Young, is an American feminist scientist and gender studies scholar. Her research focuses on social medical science, sex, gender, sexuality, and epidemiology. She is an Associate Professor of Women’s, Gender, and Sexuality Studies at Barnard College.
The neuroscience of sex differences is the study of characteristics that separate brains of different sexes. Psychological sex differences are thought by some to reflect the interaction of genes, hormones, and social learning on brain development throughout the lifespan.
In the Dominican Republic, güevedoces are children with a specific disorder of sex development. Güevedoces are classified as girls when they are born but, around the age of 12, they start developing male genitalia. This is due to a deficiency in the production of 5α-reductase, an enzyme involved in the metabolism of testosterone to dihydrotestosterone. The same phenomenon occurs in Papua New Guinea, where it is called kwolu-aatmwol by the Sambia people, and in Turkey. Anne Fausto-Sterling states that güevedoces "are recognised as a third sex" by their cultures, while the cultures "nevertheless recognize only two gender roles".
Gina Rippon is a British neurobiologist and feminist. She is a professor emeritus of cognitive neuroimaging at the Aston Brain Centre, Aston University, Birmingham. Rippon has also sat on the editorial board of the International Journal of Psychophysiology. In 2019, Rippon published her book, Gendered Brain: The New Neuroscience that Shatters the Myth of the Female Brain, which investigates the role of life experiences and biology in brain development.
The NeuroGenderings Network is an international group of researchers in neuroscience and gender studies. Members of the network study how the complexities of social norms, varied life experiences, details of laboratory conditions and biology interact to affect the results of neuroscientific research. Working under the label of "neurofeminism", they aim to critically analyze how the field of neuroscience operates, and to build an understanding of brain and gender that goes beyond gender essentialism while still treating the brain as fundamentally material. Its founding was part of a period of increased interest and activity in interdisciplinary research connecting neuroscience and the social sciences.
Giordana Grossi is a cognitive neuroscientist and professor of psychology at SUNY New Paltz, New York, and a member of The NeuroGenderings Network, a group which promotes "neurofeminism".
Neurosexism is an alleged bias in the neuroscience of sex differences towards reinforcing harmful gender stereotypes. The term was coined by feminist scholar Cordelia Fine in a 2008 article and popularised by her 2010 book Delusions of Gender. The concept is now widely used by critics of the neuroscience of sex differences in neuroscience, neuroethics and philosophy.
