Proferia, transdermal progesterone, is safe, natural and does not contain petroleum, lanolin or animal derived substances. Breast and endometrial cancer are two of the greatest fears, along with osteoporosis, that women face as they approach menopause. These fears, under present circumstances, are well warranted. However, they need not be. Among many cancers, the cause is still unknown. However, for breast and endometrial cancers, a great deal is known about it's major hormonal factors. The mystery is, why hasn't this information permeated the halls of contemporary medicine? The carcinogenic effects of unopposed estradiol, an estrogen, and the anti-cancer benefits of estriol and progesterone, are well established for these two cancers. Because of its many benefits, it's great safety, and particularly its ability to oppose the carcinogenic effects of estrogen, natural progesterone deserves far more attention and application than generally given in the prevention and care of women's health problems today.