Gender identity
Gender identity is the personal sense of one's own gender. Gender identity can correspond to a person's assigned sex or can differ from it. In most individuals, the various biological determinants of sex are congruent and consistent with the individual's gender identity. Gender expression typically reflects a person's gender identity, but this is not always the case. While a person may express behaviors, attitudes, and appearances consistent with a particular gender role, such expression may not necessarily reflect their gender identity. The term gender identity was coined by psychiatry professor Robert J. Stoller in 1964 and popularized by psychologist John Money.
In most societies, there is a basic division between gender attributes associated with males and females, a gender binary to which most people adhere and which includes expectations of masculinity and femininity in all aspects of sex and gender: biological sex, gender identity, gender expression, and sexual orientation. Some people do not identify with some, or all, of the aspects of gender associated with their biological sex; some of those people are transgender, non-binary, or genderqueer. Some societies have third gender categories.
The 2012 book Introduction to Behavioral Science in Medicine says that with exceptions, "Gender identity develops surprisingly rapidly in the early childhood years, and in the majority of instances appears to become at least partially irreversible by the age of 3 or 4". The Endocrine Society has stated "Considerable scientific evidence has emerged demonstrating a durable biological element underlying gender identity. Individuals may make choices due to other factors in their lives, but there do not seem to be external forces that genuinely cause individuals to change gender identity." Social constructivists argue that gender identity, or the way it is expressed, are socially constructed, determined by cultural and social influences. Constructivism of this type is not necessarily incompatible with the existence of an innate gender identity, since it may be the expression of that gender that varies by culture.
Age of formation
There are several theories about how and when gender identity forms, and studying the subject is difficult because children's immature language acquisition requires researchers to make assumptions from indirect evidence. John Money suggested children might have awareness of and attach some significance to gender as early as 18 months to 2 years; Lawrence Kohlberg argued that gender identity does not form until age 3. It is widely agreed that core gender identity is firmly formed by age 3. At this point, children can make firm statements about their gender and tend to choose activities and toys which are considered appropriate for their gender, although they do not yet fully understand the implications of gender. After age three, it is extremely difficult to change gender identity.Martin and Ruble conceptualize this process of development as three stages: as toddlers and pre-schoolers, children learn about defined characteristics, which are socialized aspects of gender; around the ages of five to seven years, identity is consolidated and becomes rigid; after this "peak of rigidity", fluidity returns and socially defined gender roles relax somewhat. Barbara Newmann breaks it down into four parts: understanding the concept of gender, learning gender role standards and stereotypes, identifying with parents, and forming gender preference.
According to the United Nations Educational, Scientific and Cultural Organization comprehensive sexuality education should raise awareness of topics such as gender and gender identity.
Factors influencing formation
Nature versus nurture
Although the formation of gender identity is not completely understood, many factors have been suggested as influencing its development. In particular, the extent to which gender identity is determined by nurture versus biological factors is at the core of the ongoing debate in psychology known as "nature versus nurture". There is increasing evidence that the brain is affected by the organizational role of hormones in utero, circulating sex hormones and the expression of certain genes.Social factors which may influence gender identity include ideas regarding gender roles conveyed by family, authority figures, mass media, and other influential people in a child's life. The social learning theory posits that children furthermore develop their gender identity through observing and imitating gender-linked behaviors, and then being rewarded or punished for behaving that way, thus being shaped by the people surrounding them through trying to imitate and follow them.
Large-scale twin studies suggest that the development of both transgender and cisgender gender identities is due to genetic factors, with a small potential influence of unique environmental factors.
Case of David Reimer and contrasting case
A well-known example in the nature-versus-nurture debate is the case of David Reimer, born in 1965, otherwise known as "John/Joan". As a baby, Reimer went through a faulty circumcision, losing his male genitalia. Psychologist John Money advised Reimer's parents to raise him as a girl. John Money was instrumental in the early research of gender identity, though he used the term gender role. He disagreed with the previous school of thought that gender was determined solely by biology. He argued that infants are born a blank slate and a parent could be able to decide their babies' gender. In Money's opinion, if the parent confidently raised their child as the opposite sex from earlier than age two, the child would believe that they were born that sex and act accordingly. Money believed that nurture could override nature.Reimer underwent sex reassignment surgery at seventeen months and grew up as a girl, dressing in girl clothes and surrounded by girl toys. In the early 1970s, Money reported that Reimer's sex reassignment to female was a success, influencing the academic consensus toward the nurture hypothesis, and for the following 30 years, it became standard medical practice to reassign intersex infants and male infants with micropenises to female.
After Reimer tried to commit suicide at age 13, he was told that he had been born with male genitalia. Reimer stopped seeing Money, and underwent surgery to remove his breasts and reconstruct his genitals. In 1997, sexologist Milton Diamond published a follow-up, revealing that Reimer had rejected his female reassignment, and arguing against the blank slate hypothesis and infant sex reassignment in general.
Diamond was a longtime opponent of Money's theories. Diamond had contributed to research involving pregnant rats that showed hormones played a major role in the behavior of different sexes. The researchers in the lab would inject the pregnant rat with testosterone, which would then find its way to the baby's bloodstream. The females that were born had genitalia that looked like male genitalia. The females in the litter also behaved like male rats and would even try to mount other female rats, proving that biology played a major role in animal behavior.
One criticism of the Reimer case is that Reimer lost his penis at the age of eight months and underwent sex reassignment surgery at seventeen months, which possibly meant that Reimer had already been influenced by his socialization as a boy. Bradley et al. report the contrasting case of a 26-year-old woman with XY chromosomes whose penis was lost and who underwent sex reassignment surgery between two and seven months of age, whose parents were also more committed to raising their child as a girl than Reimer's, and who remained a woman into adulthood. She reported that she had been somewhat tomboyish during childhood, enjoying stereotypically masculine childhood toys and interests, although her childhood friends were girls. While she was bisexual, having had relationships with both men and women, she found women more sexually attractive and they featured more in her fantasies. Her job at the time of the study was a blue-collar occupation that was practiced almost exclusively by men. Griet Vandermassen argues that since these are the only two cases being documented in scientific literature, this makes it difficult to draw any firm conclusions from them about the origins of gender identity, particularly given the two cases reached different conclusions. However, Vandermassen also argued that transgender people support the idea of gender identity as being biologically rooted, as they do not identify with their anatomical sex despite being raised and their behaviour reinforced according to their anatomical sex.