Since exogenous hormones, including hormonal medicines such as diethylstilbestrol (DES), have been shown carcinogenic potentials in human and animals, it has been worried about whether endocrine disrupting chemicals(EDCs) have also carcinogenic potentials at their target organs, such as prostate, mammary gland, testes, uterus, ovary, thyroid, etc. In experimental animals, mammary tumors are induced by some pesticides, such as DDT and atrazine. Although testicular tumors are also induced by some EDCs, such as DES and E2, most of tumors are interstitial cell tumors, but not germ cell tumors, which are most common testicular tumors in man. Epidemiological studies showed that there is no EDC which clearly possess carcinogenic potentials in man, except dioxin and hormonal medicines.