It is released by volcanoes and forest fires but it is a contaminant in chemicals such as pesticides and wood preservatives, and is released by incinerating trash containing plastics and paper. Dioxin also accumulates in fat. Sperm counts in men have been steadily decreasing and reproductive abnormalities have been increasing. Some of this has been attributed to increased exposure of males in the womb to too much estrogen. Exposure of males before birth to elevated concentrations of estrogen may make males more vulnerable to prostate cancer later in life.
Some synthetic chemicals can pose an even greater threat to males by acting as androgen blockers.
In women, the risk of breast cancer manifested after the menopause has been linked to lifelong exposure to estrogen. Some chemicals can alter the way in which the body processes its own estrogen. The causes of breast cancer, however, are still not well understood. The author proposes some guidelines. Filters don't remove hormonally active chemicals.