Silicone breast implants have been sold in the United States since early 1960’s, although their long term safety in human beings was not studied until the 1990’s. Because of the lack of medical scrutiny, it is not know how many women in the United States have silicone breat implants, although experts estimate one million. The major controversy that has emerged in recent years is whether silicone breast implants are safe, and whether they are responsible for the illnesses that have been reported by many of the more than 400,000 women who have filed law suits against the manufacturers.