Biological psychology stresses the importance of our brain structure, genes and hormones for how we behave. According to the biological explanation our gender is caused by what is going on inside our body-internal (sex chromosomes, hormones etc.) and are the way they are because of evolution. This usually is due to the chromosomes a person has or hormonal differences.
Every individual has 23 pairs of chromosomes. Women have 2 X chromosomes while men have an X and a Y chromosome. As an embryo, a male's Y chromosome starts to produce testosterone and other male sex hormones. These hormones help develop the testicles and penis. These androgens cause differences in the male brain and cause men to behave more aggressively than women. Oestrogen is a female hormone that controls the baby's development in the womb during pregnancy when menarche occurs and the menstrual cycle. This hormone is also responsible for changes in behaviour and can lead to pre-menstrual syndrome (or tension).
It is said that our sex is determined at conception and is universal whereas gender is malleable and cultural. Gender relates to how you perceive and see yourself. Kleinefelter's syndrome (XXY) supports that we are a product of our genes as a sufferer would have some development of breast tissue, little body hair and under development of genitals, which shows how a difference in genes can affect us. This leaves the victim with a passive temperament and poor language skills. Similarly, Turner's syndrome (X) patients have under developed ovaries, webbed/bull neck and a broad chest. They are usually of short stature and maturation does not occur at puberty. This results in affecting their spatial ability, visual memory and mathematical ability while gaining higher verbal ability. They may also have difficulty in forming social relationships especially in school. However, people with Turners