Chromosomes and Hormones.

• Gender

  Who a person is in terms of masculinity and femininity.
• Gender Identity

  An individual's perception of themselves as masculine or feminine.
• Sex

  Biological fact of being a man or woman e.g. difference in genitals at birth.
• Sex Identity

  Biological Status.
• Chromosomes

  Thread-like structures within cells that contain DNA, carrying genetic information and influencing traits and behaviours , including those related to sex and gender