The Vatican's well-known opposition to condoms stirred fresh controversy when Roman Catholic leaders announced on television that HIV is small enough to pass through condoms. The World Health Organization (WHO) and others have been furiously trying to counter the messages, saying the Vatican's stance is contributing to the spread of the AIDS epidemic.

Catholic leaders say condoms don't block HIV. Credit: Tony Gentile/Reuters

“The AIDS virus is 450 times smaller than the spermatozoon,” Cardinal Alfonso López-Trujillo, president of the Pontifical Council for the Family, said in a BBC interview on 12 October. “The spermatozoon can easily pass through the 'net' that is formed by the condom.”

Some Catholic officials manipulate people by saying that condoms encourage promiscuity, says José Santos, a physician at the Medicus Mundi organization. In Kenya, where one-third of people are Catholic and one-fifth are HIV-positive, Church representatives have publicly burned condoms. In Mozambique, where a recent survey showed that 25% of pregnant women are HIV-positive, Catholic priest Alberto Vera labeled the government campaign to promote condoms a “kind of subliminal racism.”

To counter the Vatican's message, the WHO and the European Commission have been publicizing details of research studies refuting the claim. “Condoms are part of the solution,” said Poul Nielson, Commissioner for Development and Humanitarian Aid. “The condemnation of condoms is part of the problem.”

Church officials use arguments such as that latex pores dilate in tropical heat and allow the virus in, says Manuel Corachán, head of Tropical Medicine at Barcelona's Hospital Clínic.

“[The Vatican is] going to need to come up with scientific proof,” says HIV expert Thomas Quinn of the Infectious Diseases Society of America. “There is a multitude of publications that show that the virus cannot pass through the latex of the condom.”