An US man from the state of Indiana says a blood donation centre rejected him as a donor because he appears to be gay - even though he isn't.

Aaron Pace, 22, recently visited Bio-Blood Components Inc., which pays up to $40 for blood and plasma donations. But during the interview process, he said, he was told he couldn't give blood because he seems gay.

Though Pace is "admittedly and noticeably effeminate," according to the Chicago Sun-Times, he says he's straight.

"It's not right that homeless people can give blood but homosexuals can't," Pace told the paper. "And I'm not even a homosexual."

Even though the blood bank sounds like it is engaging in a discriminatory practice, it would only be following the law by rejecting Pace were he gay. In 1983, amid the early panic over AIDS, the Food and Drug Administration banned all men who had had sex with other men since 1977 from giving blood. At that time, there were no effective screening tests to identify HIV-positive blood.

Nowadays, all donated blood in the US is tested for HIV and other infectious diseases before being given to hospitals. And a recent study found that the gay ban costs hospitals 219,000 pints of blood each year.

Curt Ellis, the former director of The Aliveness Project of Northwest Indiana, an HIV education group, called the ban "unfair, outrageous and just plain stupid."

In Australia, blood donors are asked to declare whether they have had male to male sex with or without a condom.

According to their donation information: "Anyone who has engaged in male to male sex is deferred by the Blood Service from blood donation for a period of twelve months following the last occurrence of such activity."

The reason for this is based on two factors: "The statistically higher incidence of some blood borne diseases (such as HIV) and the existence of ‘window period’ infections."

As for Pace, he's still mad about being rejected. "I was humiliated and embarrassed," he said. And just to be clear: He's not gay - not that there's anything wrong with it.