We prove in the following study, the physical mechanism of the EMF effects produced by the electric blankets and beds , on the nervous cells, and its relation with risks of breast cancer on women. Sensitivity of the melatonin compound to the EMF and its variation rates on that risks, are also studied. This study indicates the decrease of the rate of that compound with the absorbed EMF doses with time, due to the pineal gland sensitivity to the EMF (which is the main center of melatonin production) . We used the Scanning Electron Microscope (S.E.M) to show the H-ions and the free radicals formation from some DNA compounds .