estrogen dominance: an excess of estrogen in the absence of adequate levels of progesterone in women (or testosterone in men). It can result from estrogen replacement therapy, menopause, hysterectomy, birth control pills, and/or a decline in ovarian progesterone production. In men, it can result from reduced testosterone production by the testes. In either gender, it can result from exposure to pollutants and toxins (xenoestrogens). The constellation of symptoms ranges from breast tenderness and bloating, to mood swings and depression. Excess estrogens are a risk factor for the development of breast and prostate cancers.