The cause of breast cancer is unknown. However, epidemiological studies have provided information about the possible causative factors of the disease. The studies have drawn causal relationships between breast cancer and age, family breast cancer history, gender, genes, reproductive history, menstrual history, fibrocystic changes, exogenous oestrogen and diet. Additional factors include alcohol use, diethylstilbestrol use, hormonal replacement therapy and radiation. Approximately 2% of breast cancers are reported in young women who are between 20 and 34 years of age and 11% of cases are reported in women between 35 and 44 years of age. This translates into over 1500 women who are under 45 annually in Australia. Awareness of the disease is hampered by barriers which need to be investigated so that strategies to overcome them can be formulated.