Again, our bodies were never designed to/evolved to menstruate constantly, and doing so puts us at higher risk of certain cancers. Evidence suggests that the abnormal number of periods we have in modern life elevate our breast cancer risk. The pill has both potential risks and benefits -- for example, it cuts your risk of ovarian and endometrial cancers by reducing the number of ovulations in your lifetime. (It produces the same effect as if you'd had a number of children and breastfed them for several years). I would recommend every woman educate herself and talk to her doctor. There is no absolute best choice that applies to every woman in every situation. Having years of periods is by no means always healthier or more natural, though.