In general, what is considered the best form of birth control for younger, breeding females today? My seventeenth edition copy of the Merck Manual has a description of each method, and it is overwhelmingly clear that one method is best. The copper IUD has a 2% failure rate over 10 years, equivalent to sterilization, and does not interfere with female hormone cycles. As I understand it, all of the hormonal birth control methods have several unwanted effects. Common, significant "side effects" are changes in which MHC pheromones females respond to, reduced sex drive, and weight gain. These 3 "side effects" probably occur in almost all women, as estrogen is thought to cause each of these effects. I read recently that the copper IUD has fallen out of favor, because there is a small risk of uterine infection that can result in permanent sterility. It is also painful and expensive and invasive to install. However, as near as I can tell, it appears to be the "best method" by an overwhelming margin. It is the most effective, requires nothing of the patient, and after the first few weeks causes essentially no systemic side effects in most women. But with IUDs off the table, what is now considered the "best method" of birth control for women who intend to have children in the future?