found that women's risk due to radiation exposure exceeded men's by 37.5 percent. When one considers rates of cancer incidence separately from rates of cancer fatality, the sex disparities are even greater. The BEIR VII Committee concluded that, given the same level of radiation exposure, women are 52 percent more likely than men to develop cancer, while the EPA report puts the estimate of difference as high as 58 percent. The differences in risk are even greater when considering organ-specific cancers, especially given that both reports identify breast, ovarian, lung, colon, and thyroid tissues as the most radiosensitive among women. For example, the FGR 13 has estimated that the ratio of thyroid cancer incidence for women as compared to men is 2.14, while the findings of BEIR VII suggest that women are even more vulnerable to radiation-induced thyroid cancer at a ratio of 4.76. As increasing concerns are raised regarding the environmental risks related to breast, the BEIR VII report cited evidence that suggests that "radiation may interact synergistically with other risk factors for breast cancer", raising the possibility that endocrine disrupting chemicals like PCBs and dioxins might combine to increase the risks associated with radiation beyond that which would be caused by either separately. A related concern is that radionuclides that may be passed through the breast milk, causing some women who are downwinders to be reluctant to breastfeed their children. While reducing the radioactive intake of their infants is an important preventative measure, it denies women the opportunity to engage a preventative measure for their own health; i.e. breastfeeding has been widely documented as a practice that can reduce women's risk of developing breast cancer. By refraining from breastfeeding, women downwinders' risks of breast cancer incidence becomes even more elevated. Pregnancy and birth outcomes Evidence about radiation-related pregnancy and birth outcomes comes from studies of nuclear bomb and test site survivors and studies of those exposed to diagnostic and therapeutic radiation. Mounting research indicates that above certain levels of radiation a miscarriage will result. It is also clear that fetal malformations are a greater risk if a woman is exposed to high doses of nuclear-related radiation in early pregnancy, when organs are being formed. If acute radiation exposure occurs in the first ten days following conception, when few cells have formed, it is likely that the embryo will fail to develop and spontaneous abortion will occur. Fetal malformations