While top AIDS researchers are meeting in Bangkok this week, some scientists from U.S. government agencies are absent.
This year's U.S. delegation numbers 50 people, far fewer than the 236 who attended the international AIDS conference two years ago in Barcelona.
Anthony Fauci, of the U.S. National Institutes of Health, said that the reason is allocation of resources.
"The decision was made that the money would be spent better by just funding research," he said.
But Democratic Congresswoman Barbara Lee says money is not the issue.
"I am not sure what the rationale is, but the funding is there. And I know that and they should be here. This is an important conference," she added.
Some speculate the delegation was cut back because the conference does not focus enough on abstinence, the Bush administration's preferred HIV prevention method. Others trace the cut to the Barcelona conference, where AIDS activists disrupted a speech by Health and Human Services Secretary Tommy Thompson.
Joep Lange, one of the organizers of the conference, supports free speech at the conference, but he said that the treatment Mr. Thompson received in Barcelona was out of order.
"Some things that happen at this conference are totally counter-productive," he noted. "The shouting down of Secretary Thompson has done a lot of harm."
Chief editor Cathy DeAngelis of the prestigious Journal of the American Medical Association says cutting the delegation is petty. And she said that the Bush administration is getting in the way of free scientific expression.
"Our nation is supposedly the leader in research," she said. "To deprive many of our scientists who are doing this research from coming here and sharing their knowledge and learning from others, I just think that that is wrong."
Experts say the impact of the smaller U.S. delegation on the conference will not be devastating, but the presence of more U.S. researchers would have been helpful.