Nonoxynol-9 (N9) has been used as a spermicide on diaphragms and condoms for many years. When test-tube studies suggested it could kill the AIDS virus a study involving 999 prostitutes in South Africa, Benin, Thailand and the Ivory Coast was undertaken. The researchers were shocked by the results. The more the women used N9 products, the greater their risk of contracting AIDS seemed to become. The researchers suggest that it may damage the skin inside the vagina, making it easier for the AIDS virus to enter.

The researchers also hoped that N9 might protect against gonorrhoea and chlamydia. It did not. The study's director, Dr. Lut van Damme of Antwerp's Institute of Tropical Medicine (Belgium), commented that "this may be the end of nonoxynol-9 as a potential microbe killer" and called for messages including its use as part of a safe sex programme to be considered.

Ed.- In 1996 S.D. Fihn and colleagues discovered that, by inhibiting the growth of beneficial vaginal bacteria, exposure to nonoxynol-9 increased women’s chances of contracting a urinary tract infection by three and a half times. Nonoxynol-9 is part of the ethoxylated alkylphenol family, which includes some of the most powerful oestrogenic gender-bending chemicals invented.