Predisposing factors seem to include a long lifetime of unopposed oestrogens circulating in that the disease is more common in those who had an early menarche, a late menopause and never been pregnant.
The fact that the disease is less common in those who have had multiple pregnancies fits in well with this thesis and the oral contraceptive pill (low oestrogen) is thought to be protective.
There is unquestionably a genetic predisposition to this disease in some patients and there has been much fruitful research recently on this topic. Where a woman has one affected first degree relative with the disease, there is a 2.5% risk (twice background) that she will contract the disease. Where there are two first degree relatives with the illness there is a 25% chance that she will contract ovarian cancer also. In families such as the latter instance there are commonly other cancers represented within the family and particularly breast and colorectal cancers. The predisposition oncogene BRCA, which has already been mentioned in connection with breast cancer, is also one the best worked out familial predisposition genes for ovarian cancer.