Sexuality is an important part of how we think about ourselves and how others think about us. A female ovum & male sperm combine to form a fertilized embryo: the pair determines the child"s sex; If father contributes x female embryo (xx) If father contributes a y male embryo (xy: about 105 boys are born for every 100 girls but higher death rate among males making females majority by mid-thirties. From birth, the 2 sexes have different primary sex characteristics the genitals (organs used for reproduction) It has been apparent that girls are reaching puberty at earlier ages than previous generations, recently discovered that boys too are reaching puberty at younger ages. Note: sex is not the same as gender; gender is an element of culture that refers to personal traits. & patterns of behaviour (including responsibilities, opportunities, privileges) Intersexual people: refers to people whose bodies (including genitals) have both female & male characteristics.