African American men were the least likely to know they were HIV positive, with 91 percent unaware of their status, according to the study, led by Duncan MacKellar of the Centers for Disease Control and Prevention (CDC).

More than 5,700 MSM were surveyed (between 1994 and 2000) in six different cities in the United States. The MSM were between the ages of 15 and 29, and 60 percent of infected white MSM and 70 percent of infected Hispanic MSM also did not know they were infected.

Many of the HIV infected men didn’t think they were at risk for HIV with 59 percent thinking they were at low or very low risk, even though more than half had unprotected anal intercourse with other men in the previous six months. In addition, nearly half had three or more male sex partners during that time period.

It is important not to stigmatize these communities, Ronald O. Valdiserri, M.D., M.P.H, deputy director of the National Center for HIV, STD and TB Prevention (NCHSTP), CDC, pointed out during a teleconference on July 3.

"I think it’s very important for the media and for policy makers to understand what this means and not inadvertently stigmatize these populations," he said.

There are several factors that help explain the lack of testing and education. "We think there are a number of reasons at play here," Dr. Valdiserri said. "Part of it has to do with the complicated psychology behind the perception of risk that truly many of these men, perhaps because of their age and ongoing social circumstances may not appreciate that they are putting themselves at risk," he said.

While the men may be engaging in sex with other men, Valdiserri couldn't say whether they identify as gay or bisexual.

"I don’t have that data available. That is something that we might have to follow up on," he said. "There has certainly been other research indicating that levels of sexual identification are an important component in this mix of risk and how one might identify that risk but I don’t have that data available at hand."

As for the racial disparities within the population of MSM, Valdiserri points to the ongoing health disparities with racial and ethnic groups in the US. "These men may not have access to services that would permit them to either learn more about HIV or learn about their sero-status. It’s very important that we understand it and not further stigmatize these populations."