Causes of Cancer
Reproduction and hormones
There is a strong connection between female genital cancer and Breast Cancer and sexual and reproductive behaviour. If a woman has multiple sexual partners, she may have a greater risk of developing Cervical Cancer. The number of their male partner’s sexual partners also affects the risk of developing Cervical Cancer between women. This may be explained by the fact that sexual contact with infectious viruses is significant in Cervical Cancer pathogenesis.
To give birth at an early age and to have several children protects against Breast Cancer. If the woman has a very large number of children, the protective effect is emphasised.  Infertility also constitutes a risk factor for ovarian and endometrial cancers. Early sexual maturity and late menopause increase menstrual cycles and the incidence of the above cancers.
Breast, endometrial and ovarian cancers are more frequently diagnosed during menopause in women who use long-term Hormone therapy. [17-19] Progesterone, combined with replacement oestrogen therapy, increases the risk of Breast Cancer but, in turn, protects against endometrial cancer. [17, 18, 20] Accordingly, the effects of oestrogen replacement therapy in the treatment of menopause should be assessed individually in relation to the risk of cancer, inter alia.
For men, elevated levels of male hormone, i.e. androgen, are likely to be associated with an increased risk of Prostate Cancer.