Hormones in oral contraceptives (OC) and hormone replacement therapy (HRT) have been linked with some types of cancer, as are increased levels of estrogen. (www.ncbi.nlm.nih.gov/) Aromatase in fat cells, especially belly fat, converts testosterone to estrogen in both males and females. This can be very problematic for both genders.
Prevention? Maintaining your weight in an optimum range and preventing excess belly fat can decrease testosterone-estrogen conversion. Think carefully about hormonal supplements and do so with good medical supervision.