In a letter explaining his withdrawal, Jerry Thacker, who had also railed against "the sin of homosexuality", claimed his reference to a gay plague was made when "describing the historical context" of Aids and was taken out of context. He advocates abstinence programmes and "reparative therapy" to treat "aberrant" homosexual behaviour.

News of his appointment on the 35-strong advisory panel prompted an avalanche of criticism.

The Senate minority leader, Tom Daschle, said: "Thacker's characterisation of Aids as the gay plague and his offensive public statements about homosexuality indicate a disturbing bias that is completely at odds with the role the advisory commission should play."

The White House was quick to disown Mr Thacker's views on HIV and Aids. "That remark is far removed from what the president believes," said Mr Bush's press spokesman, Ari Fleischer. "The president's view is people with Aids need to be treated with care, compassion."

But gay rights activists said that while the withdrawal was welcome, the initial appointment was indicative of the Bush administration's "inadequate attitude" towards HIV and Aids.

"The underlying problem remains," said David Smith, a spokesman for the Human Rights Campaign, the country's biggest gay and lesbian advocacy group.

"Their single-minded focus on abstinence as the only mechanism for preventing the transmission of HIV is unrealistic, not based on science, and could cause enormous harm."

Mr Thacker is HIV positive, having contracted the virus from his wife who was infected by a blood transfusion in 1984.

Before she was aware that she had the virus, she passed it on to her husband and daughter.

Mr Thacker said he was not anti-gay. "I am, however, anti-HIV/Aids," he wrote.

"The three infected people in our family - my wife, daughter and myself - would not wish this disease on any other human being."

Of the panel as a whole, to which seven new members have been appointed, the HRC said: "There are several good appointments, and the overall picture is a mixed bag.

"But Thacker was beyond the pale. We hope someone would be held accountable for putting his name forward."