In particular, risk-reducing bilateral oophorectomy also confers protection against ovarian cancer, a strategy relevant to BRCA1/2 carriers and other women with hereditary breast/ovarian cancer; oophorectomy has side-effects for premenopausal women, such as loss of fertility and sudden onset of menopause; and tamoxifen has been shown to be associated with an increased risk of endometrial cancer, deep vein thrombosis and pulmonary embolus. This evidence concerns the gene BRCA1 and deep vein thrombosis.