4.3.3 - Biological explanations of gender development

Biological influences on gender development

A biological explanation of gender development argues that gender-related behaviour and, to some extent, gender identity are influenced by inherited and bodily processes. In this lesson, the focus is not basic biological sex. That belongs to the neighbouring lesson on chromosomes, hormones and diversity in sex development. Here the question is more explanatory: how might chromosomes and hormones help shape the development of gendered interests, roles, expression and identity?

Biological explanations usually make a chain of reasoning:

1. Chromosomes influence the development of gonads and hormone patterns.
2. Hormones, especially androgens such as testosterone, can affect developing body systems and brain systems.
3. Those biological influences may make some gender-related behaviours more or less likely.
4. The person still develops in a social world, so biological influences interact with family, peers, culture, cognition and personal experience.

That last point is essential. A modern biological explanation should not say "chromosomes determine gender" as if every person with a particular chromosome pattern must develop the same identity or behaviour. It is more accurate to say that biological factors can influence probabilities and developmental pathways.

AO1: what to know. Biological explanations use chromosomes and hormones as internal influences on gender development. They are nature-based explanations, but they do not have to be hard determinist.

AO2: how to apply it. If an item supplies evidence of higher prenatal androgen exposure, a biological explanation can link that exposure to later activity interests. Activity preferences alone do not reveal hormone levels: climbing, dolls or competitive games are choices anyone can enjoy. Use the supplied biological evidence rather than inferring a body characteristic from a stereotype.

AO3: exam caution. AQA can reward biological evidence, but high-level answers avoid turning group averages into rules about individuals. "More likely" is usually safer and more scientific than "will".

Chromosomes as a starting point

Chromosomes matter because they can set up early biological pathways. In a typical pathway, an embryo with a Y chromosome has the SRY gene, which usually leads to the development of testes. The testes produce androgens, including testosterone, and this changes the prenatal hormone environment. In a typical XX pathway, there is no Y-linked SRY signal, so a different pattern of gonadal and hormone development usually occurs.

This basic pathway belongs partly to biological sex, but its relevance here is explanatory. Chromosomes do not directly "write" gender behaviour. Instead, they can influence the hormone environment in which the body and brain develop.

AO1: chromosome route.

Evidence from cases where chromosomal/hormonal factors and social rearing do not match is often used in this topic. The best-known case is David Reimer. Diamond and Sigmundson (1997) reviewed the case of an XY child whose penis was accidentally destroyed in infancy and who was raised as a girl after sex reassignment. The child later rejected the female assignment and lived as male. This case challenges the idea that gender identity can be created entirely by rearing.

Reiner and Gearhart (2004) provide broader, though still small-sample, evidence. They assessed 16 genetic males with cloacal exstrophy, a severe congenital condition. Fourteen had been assigned female socially, legally and surgically in infancy; eight of those 14 later declared themselves male. This challenges an account in which female social assignment is sufficient to produce a female identity in every case. It is consistent with prenatal biological influence, but chromosomes, hormone exposure, medical treatment and social experience were not separated experimentally.

AO3: why this evidence must be handled carefully. Case studies and rare clinical samples are valuable because they create situations that cannot be ethically produced in experiments. However, they are not typical development. The medical history, surgery, family context and social responses all matter. Reimer's life should be treated as socially sensitive evidence, not as a simple exam slogan.

Hormones and sensitive periods

Hormones are chemical messengers. In gender development, the key idea is that hormones can have different effects depending on when they act. Prenatal and early neonatal hormone exposure may help organise developing systems. Later hormones can activate or modulate existing systems. This is a useful distinction between types of effect, not an absolute rule that all early effects organise and all pubertal effects only activate: puberty can also involve lasting reorganisation.

This is often called the organisational-activational account. It does not mean a child has a fixed "male brain" or "female brain". It means that early hormones may influence some developing neural systems, and those influences may later combine with puberty, learning and social experience.

AO1: testosterone and androgens. Testosterone is the hormone most often discussed. It is higher on average in typical prenatal male development during key periods of gestation. Research reviews by Hines and colleagues report that early androgen exposure is most consistently linked with childhood sex-typed play and activity interests. The most consistent human findings concern particular play and activity measures; they do not justify a general claim that testosterone produces “masculinity” as one unit.

AO1: oestrogens and other hormones. Oestrogens also play important roles in development, puberty and brain function, but AQA gender-development answers usually focus more on androgens because the evidence base for sex-typed play and activity interests is clearer. Oxytocin is sometimes linked with bonding and social affiliation, but it is risky to present it as a simple explanation of "female nurturing". Both males and females produce oxytocin, and social context strongly affects bonding.

AO2: applying the sensitive-period idea. Jaya is 10 and has a condition that exposed her to higher-than-usual androgens before birth. She identifies as a girl, but she strongly prefers climbing, construction toys and competitive games. A biological explanation could argue that prenatal androgen exposure influenced her activity interests. It should not claim that her identity is automatically changed, because hormone effects are uneven across different gender-related outcomes.