The new rule has created confusion among health groups, wondering how it will affect them, and has drawn criticism from others who say it infringes on free speech rights and could do more harm than good.
It will affect about $2.2 billion in AIDS grants and contracts this year, said Kent Hill, acting administrator for global health at the U.S. Agency for International Development, which issued a policy directive outlining the regulation.
Hill said the pledge is a way for the United States to take a stand against a life he called degrading and debilitating.
"Prostitution is not a positive for the people who are involved in it," Hill said. "The vast majority of people, globally, do not find themselves there by choice."
One of those troubled by free speech issues the pledge requirement raises is Terri Bartlett, vice president for public policy at Population Action International, a health advocacy group for women's issues.
"There's a litmus test of issues and organizations' positions on those issues, and regardless of their ability, they will be judged by that position," Bartlett said.
Bartlett said while she agreed with the pledge requirement's premise that prostitution is a harmful occupation, it may have the unintended effect of deterring prostitutes from seeking help by unnecessarily singling them out.
"We want to build trust and reduce stigma," Bartlett said, speaking of people in the high-risk world of prostitution. "This policy flies in the face of what we know works."
Congress ordered the pledge requirement in 2003. It was immediately applied to foreign aid recipients, but the Justice Department questioned the constitutionality of applying it to domestic organizations. Last fall, the department gave the all-clear for the government to implement the requirement here as well.
The rule now affects private U.S. groups in their conduct of AIDS programs overseas. If a group seeks a federal grant or contract, it first must adopt a statement that it explicitly opposes prostitution and sex trafficking. Then it must sign a government form that it has the policy. Only then is the organization eligible to receive money under President George W. Bush's showcase program to fight HIV-AIDS abroad.