Recent worldwide media speculation that silicone gel-filled breast implants may be linked to an increased incidence of breast and other cancers, and connective tissue disease (particularly systemic sclerosis) has caused concern to the medical profession and public alike. Until carefully controlled studies have been performed to prove the safety of these implants, the US Food and Drug Administration has restricted their use to research and breast reconstruction. Research has so far failed to prove a causative relationship between silicone implants and cancer or connective tissue disorders.