The role of chromosomes and hormones in sex and gender

Question 1

What is a chromosome?

Answer 1

The X shaped bodies that carry all the genetic information (DNA) for an organism

Question 2

What are hormones?

Answer 2

The body’s chemical messengers

Question 3

what does the term intersex refer to?

Answer 3

a term used to describe an individual who is neither distinctly male or female because of a mismatch between, for example, chromosomes and genitals

Question 4

What are the typical chromosome patterns?

Answer 4

each person has 23 chromosomes

Question 5

Describe one atypical chromosome pattern

Answer 5

Klinfelter’s syndrome
- occurs due to an XXY configuration
- The individual is born a with a penis and develops as a fairly normal male
- happens to 1 in 1,000 males
- characteristics include: Taller than average, less muscular coordination than average, physically looking less masculine because of reduced levels of testosterone e,g less facial hair, broader hips, and possible breast tissue
- such individuals are often infertile

Question 6

Name a second atypical chromosome

Answer 6

Turner’s syndrome:
- Occurs due to an XO configuration
- the second sex chromosome is partly or completely missing
- occurs in about 1 in 2,000 females at birth
Common characteristics include: shorter than average, lack of monthly periods due to underdeveloped ovaries, lower jaw, webbed neck, narrow hips and misshapen internal organ

Question 7

Explain the impacts of testosterone in sex and gender

Answer 7

• testosterone is produced prenatally (before birth)
• Some XY individuals have an insensitivity to such hormones (their body tissue did not respond to the effects of the hormone)
• this could lead to no development of external genitalia (in extreme cases)
• Such individuals are usually identified as females during birth and raised as girls
• testosterone also affects brain development both prenatally and later in childhood
• Berenbaum and Bailey 2003 found that XX females exposed prenatally to relatively large doses of testosterone showed more tomboyish behaviours and greater interest in male activities.

Question 8

Explain the role of oestrogen in sex and gender

Answer 8

• oestrogen plays a major role from puberty onwards, promoting secondary sexual characteristics (such as breast development)
• it is also involved in directing the menstrual cycle

Question 9

Explain the role of oxytocin in sex and gender

Answer 9

• called the love hormone as it promotes feelings of bonding in both men and women
• it is produced in the pituitary gland and evokes feelings of calm and contentment
• in women, this hormone is important in breast feeding because it causes milk to flow in a lactating mother
• in men and women Oxytocin is related to orgasms and faster wound healing
• at times of stress, it dampens the stress response in flight or fight (Taylor et al 2000)
• this evolved response ensures that females protect their young (tending) and form protective alliances with other women (befriending)
• the same does not happen in men because testosterone dampens the effects of oxytocin