Biological Explanations of Gender Development (AQA A Level Psychology): Revision Note

The role of chromosomes in gender development

• The World Health Organisation (WHO) states that gender refers to the socially constructed characteristics of men, women, girls, and boys

  • This covers relationships between people as well as the norms, behaviours, and roles that come with being a girl, boy, woman, or man

  • Gender as a social construct differs from society to society and is subject to change over time

• Chromosomes may shape gender identity; their role is complex and multifaceted, as many traits and characteristics of a person are determined by their unique set of chromosomes, passed down from parents to offspring

• Genetic transmission explains how individuals acquire their biological sex, but it can also explain some aspects of gender because of the link between genes, genitalia and hormones

• In humans, biological sex is determined by the sex chromosomes

  • In females, the sex chromosomes are the same (XX)

  • In males, the sex chromosomes are different (XY)

  • They determine a person’s biological sex at fertilisation

    • If an egg is fertilised by a sperm carrying a Y-chromosome, the child will be biologically male

    • If the sperm carries an X chromosome and fertilises the egg, then the child will be biologically female

  • The Y chromosome carries the SRY (Sex-determining Region Y) gene, which triggers male development by causing the development of testes (rather than ovaries) and activating the production of androgens

    • Androgens cause the embryo to become biologically male, and without them, the embryo develops into a female

The role of hormones in gender development

• Most gender development is governed by hormones

• Testosterone:

  • This is produced in much greater quantities in males, whereas the hormones oestrogen and oxytocin are produced in greater amounts in females

  • Testosterone affects the development of genitalia and brain development, both prenatally and later in childhood

    • E.g., it sets a template for later male-typical play and rough-and-tumble behaviour

  • During puberty, testosterone increases sensation-seeking, risk-taking, sexual motivation and competitiveness

  • During adolescence and adulthood, testosterone:

    • modulates dominance, status-seeking and assertiveness

    • intensifies motivation for social rewards and sexual pursuits

    • slightly enhances certain spatial abilities (e.g., map reading)

• Oestrogen:

  • This hormone determines female sexual characteristics and directs the menstrual cycle

  • Alongside physical changes, oestrogen is closely linked with the emotional well-being of women as it affects parts of the brain that control emotion

  • It plays a role in mood changes associated with conditions such as premenstrual tension (PMT), premenstrual dysphoric disorder (PMDD), and postpartum depression

    • PMT affects as many as 90% of women who have symptoms before their periods, such as feeling overly emotional, depressed, angry, irritable, anxious, or socially withdrawn

    • Women with PMDD regularly develop negative mood symptoms before their periods, such as feeling very sad, hopeless, or worthless

  • This shows how hormones influence aspects of gender specific behaviour, as research shows depression affects women more than men (Salk, 2018)

• Oxytocin:

  • Oxytocin promotes feelings of bonding in both men and women

  • Women typically produce more oxytocin than men, and it is amplified by oestrogen; therefore, oxytocin contributes to gender differences

  • Oxytocin helps form an emotional bond between mother and baby; therefore, this hormone partly explains gender specific stereotypes such as mothers being more nurturing than fathers

  • At times of stress, oxytocin dampens the fight-or-flight response and triggers the ‘tend and befriend’ response in females to ensure that they look after their young and form bonds with other women

Research on the role of chromosomes and hormones in gender development

• According to Berenbaum and Bailey (2003), XX females exposed to high levels of male hormones during pregnancy (as their mothers had been given drugs that contained male hormones) subsequently displayed more tomboyish behaviour, higher levels of aggression and a greater interest in male-type activities

  • This shows how hormones influence aspects of gender specific behaviour

• Van Goozen et al. (1995) found that transgender women (male-to-female) who were given oestrogen treatment showed decreases in aggression and visuospatial skills, while transgender men (female-to-male) treated with testosterone showed the opposite effects 

• Oestrogen levels have feminising effects on brain development. Schultheiss et al. (2020) suggest that oestrogen exposure explains why women generally have greater verbal fluency than men

• Dabbs et al. (1995) found that offenders with the highest levels of testosterone were more likely to have committed violent or sexually motivated crimes

Evaluation of the biological explanations of gender development

Strengths

• Research suggests that biological factors have a key role in gender development, e.g., Reiner & Gearhart (2004) studied 16 genetic males with no penis: 14 were raised as female; 8 of these 14 participants reassigned themselves as males by the age of 16

• Quadagno et al. (1977) found that female monkeys who were deliberately exposed to testosterone during prenatal development later engaged in more rough-and-tumble play than other females

Weaknesses

• Other factors are important in the development of gender, as genetic sex doesn't match external genitalia in cases of abnormal hormone exposure. The outcome for such individuals appears to be a complex and unpredictable combination of genes, hormones and socialisation

  • This shows that there isn't a simple relationship between hormones and gender-specific behaviour in humans

• Many non-Western cultures have embraced multigender systems where gender identities other than man/woman are recognised, e.g., the Hijra in India, Muxes in Mexico and the Bugis people of Indonesia

  • This shows that gender is fluid and that gender roles, identities, and expectations are socially constructed rather than solely based on biology

Link to Issues and Debates:

The research into the biological explanation of gender development is biologically reductionist and deterministic, ignoring the complexities experienced by individuals growing up with intersex conditions such as congenital adrenal hyperplasia (CAH). Research shows that gender assignment at birth seems to be accepted by some individuals but not others, showing that gender development is part biologically determined (nature), but experience, culture, personal qualities and socialisation (nurture) also play a key role