João Campos, the Brazilian lawmaker who drafted legislation that would allow psychiatrists in Latin America's largest country to treat homosexuality as a disease, asked that the bill be withdrawn on Tuesday, according to a congressional website.
Opponents of the legislation, popularly referred to as the "gay cure" bill, moved on Tuesday to bring the matter to a vote before the entire Chamber of Deputies, Brazil's lower house of Congress.
Campos' request came as it became clear that the legislation was going to be roundly defeated by the chamber.
The bill was aimed at overturning the Brazilian Psychiatry Association's prohibition against treating homosexuality as a disease or mental disorder.
Official withdrawal of the bill will require a vote by lawmakers, but with the loss of support from Campos and Marco Feliciano, who heads Chamber's Human Rights and Minorities Committee, it appears likely.
Feliciano is an Evangelical pastor and congressman who has sold more than 600,000 self-help books and DVDs. He gained prominence in recent years for his fundamentalist Christianity and conservative social views.
Opposition to the "gay cure" bill is one of the main issues being taken up by participants in nationwide street protests that began in June over inadequate public services and government corruption.
"Help me, doctor - I woke up gay today!" read the sarcastic sign of one protestor in Rio de Janeiro last month.
Though she avoided making public comment on the matter, Brazilian President Dilma Rousseff met with groups representing gay, lesbian, bisexual and transgender people on Friday to demonstrate her support.
"Today we are celebrating," said Guilhermina Cunha, a vice-president of the Brazilian GLBT Association. "The next step, however, and we we're not yet sure how to do it, is to remove Feliciano from his position."