1992: The FDA bans silicone-gel breast implants, except for patients with breast cancer and certain other conditions that could get them through specially monitored research studies. Implants filled with saline or salt water, were not restricted and were the only option left for cosmetic enlargement in the USA.

1999: The Institute of Medicine, an advisory arm of the National Academies, says there was no evidence linking breast implants to serious illnesses, but that breaking, pain and other local complications may occur.

2000: The FDA re-evaluates saline-filled implants and declares them safe enough to continue selling if women are warned about high breakage and replacement rates.

2003: Inamed Corp. asks the FDA to approve its silicone-gel implants in the USA.

2003 October, a panel of FDA scientific advisers recommends that the implants be allowed to return to the US market.

January 2004: The FDA rejects Inamed's bid to bring silicone-gel implants back to market and asks the company for more information to ensure the implants are safe.

In keeping the implants off the market for the time being, FDA took the highly unusual step of rejecting the recommendation of its own scientific advisers, who in October had reluctantly agreed the devices should return despite some lingering questions about safety and durability.

Inamed said the company would seek approval again after learning exactly what additional information the government will require as proof that silicone gel implants are safe enough to sell.

Silicone implants do not cause major disease

The Institute of Medicine, an arm of the National Academy of Sciences, recently concluded that women with silicone breasts implants are no more likely than the rest of the population to develop serious illnesses. The report said new studies have led to, among others, the following conclusions: