Nearly 10 percent of men who told public health pollsters they were straight also told them they'd had sex with a man in the previous 12 months, according to a study conducted in New York City.
While significant questions remain about how reliable these figures are, experts in gay men's medicine say it's a real phenomenon among all ethnic groups and one that should be publicized more.
"It's found among all groups, certainly including white males," said Dr. Stephen Goldstone, whose practice at New York's Mount Sinai Hospital treats mostly gay men.
Recent reports, including a segment on "The Oprah Winfrey Show," have publicized the practice known among African American men as "the down low," in which men "love their wives but have sex with men" -- and don't identify themselves as homosexual.
The new study, based on a 2003 phone survey of 10,000 residents by New York's public health department, found that 38 percent of the men (who said they were straight but had had sex with a man in the previous year) were white, 29 percent were Hispanic, 23 percent black and 10 percent Asian, multiple race or other.
Though there are questions about how accurate the study is, the researchers and health professionals agree that the underlying message is important.
"We still have a lot to learn about how to ask people about this sensitive issue," Dr. Harold Sox, editor of the Annals of Internal Medicine, told ABC News. "The main reason we published it was to send a clear message for doctors -- that it's not enough to just ask a person's sexual identity."
Goldstone agreed that many doctors have a long way to go.
"Sometimes, doctors even assume that because a man has a wedding ring, he's not having sex with men," he said. "The labels homosexual or heterosexual or gay and straight are simply not enough. Doctors must ask specifically 'What are you doing -- have you had sex with a man?'"
"I didn't need this survey to give me the general picture," said Goldstone, who has been treating gay men in the New York area for three decades and is also a professor at Mt. Sinai. "We're now taking great care to teach our medical students about this."
The extreme sensitivity of this issue among most respondents makes it difficult to get accurate statistics, as the study's lead author, Preeti Pathela, admits.
In fact, simply reversing the order of some questions produced a markedly different result, as suggested by preliminary data from a similar survey by the group two years later. Asking the men about women partners first, and then about men partners -- switching the 2003 order -- "resulted in a much lower" percentage of men who said they'd had sex with men.
The 2003 study also reports that the men, when compared to men who say they are gay, are more likely to:
belong to a minority racial or ethnic group,
be foreign born,
have a low educational level.
They are also less likely to have been tested for HIV in the previous year and to have used a condom in their last sexual encounter, the study said.
There's important news there for wives, says Pathela. Seventy percent of the men said they were married. (The study does not report how many men may have come out to their wives.)
Whatever the Exact Percentage, Internet May Help
Experts say that whatever the exact percentage of men who say they're straight but have sex with men, the Internet promises to provide them with important medical information by leapfrogging sensitive issues of denial and deception.
"In the privacy of their rooms, there are now places gay men can Google to get answers about issues they may find hard to talk about with pollsters or their doctors," said Goldstone, who runs a website at GayHealth.com.
He says his long experience with the many ethnic groups in New York has taught him that virtually all cultures still have intimidating prohibitions against gay sex.
"It's not safe to be gay in most parts of the world, including large parts of the United States," he said.