Men who have sex with men (MSM) aren’t the only people who get HIV.

There are also high-tech tests that can detect HIV, as well as other viruses, in blood less than two weeks after a person has been infected.

So why are there still restrictions on MSM when it comes to donating blood?

This question was raised yet again this summer after a mass shooting at a nightclub in Orlando, Florida.

Many in the MSM community wanted to give blood in support of those injured in the attack. However, they were turned away due to Food and Drug Administration (FDA) guidelines that prohibit blood donations from any man who has had sex with another man within the past year.

That policy is meant to keep individuals who may be infected with HIV from contributing to the blood supply, but critics say it is outmoded and unnecessary.

“They’re calling it a deferral, but if you think of a monogamous married gay male couple, they are at a very, very low risk of contracting HIV or AIDS and yet they are categorically denied, assuming that they are sexually active,” Robin Maril, an associate legal director at the Human Rights Campaign, told Healthline.

Protecting blood

The FDA keeps HIV and other bloodborne diseases out of the blood supply in two ways.

First, it recommends that every bag of blood be screened for HIV, hepatitis, West Nile virus, and other diseases.

While the guidelines are not mandatory, blood banks must follow them or submit alternative plans to meet minimum safety requirements.

The agency also suggests that people who are at a relatively high risk for contracting these diseases be deferred or banned from donating blood.

Groups considered too risky to give blood include intravenous drug users, commercial sex workers, and people who have traveled to countries where there is malaria.

The FDA considers MSM to be one of these high-risk groups. That prohibition has been in effect since 1985, an era when relatively little was known about the AIDS virus and screening technology was nowhere near what it is today.

Originally, the policy instituted a lifetime ban on blood donations from men who had sexual relations with other men, even if it was a single time.

In 2015, the FDA amended the policy to a prohibition against men who have had sex with other men in the past year.

Read more: Blood donations at critically low levels »

Looking at the risks

There’s no question MSM continue to be disproportionately affected by HIV in this country.

Of the 44,000 new HIV infections reported in the United States in 2014, almost 30,000 occurred in MSM.

But more than 10,000 other cases came from heterosexual contact. That’s in comparison to 2,635 people who contracted the virus through injection drug use.

In addition, antiretroviral drugs and increasingly sensitive HIV tests have changed the blood donation landscape dramatically — changes that critics say haven’t been reflected in the FDA’s policy.

Current tests can detect HIV in donated blood as early as nine days after a person is infected.

That’s a short window during which blood from an infected person would slip past surveillance.

So why recommend a whole year of celibacy?

FDA spokesperson Paul Richards told Healthline the 12-month period has been well-studied. Among other things, it was found to maintain the safety of the blood supply in Australia, a country with HIV epidemiology and blood screening systems similar to the United States.

To further reduce the risk, he added, potential blood donors are asked a series of questions that include their medical history, drug use, sexual patterns, and countries they’ve visited.

Those safeguards, he noted, have reduced the chances of contracting HIV through a blood transfusion in the United States to about 1 in 1.5 million.

In 2011, about 21 million blood components were made available for transfusion to 5 million people in the United States.

“The FDA's deferral recommendations are based on medical, behavioral, and geographical risks for transfusion-transmissible infections,” Richards said. “Under existing regulations, the FDA defers other donors when they present similarly high risks for exposure to transfusion-transmissible infections.”

Louis Katz, chief medical officer at America’s Blood Centers, says the rules get down to how low a risk is acceptable for someone about to get a blood transmission.

Is something higher than 1 in 1.5 million good enough?

“It’s not a trivial question,” Katz told Healthline.

Read more: Should you store or donate umbilical cord blood? »

Policy criticisms

Maril and others, however, say the FDA’s policy is outdated and discriminatory.

Among other things, Maril asks why men who practice safe sex with other men are still banned from donating blood.

There’s also the fact that heterosexual couples aren’t quizzed about their sexual practices.

In Italy, all potential donors are asked questions about their sexual history and condom use, regardless of their sexual orientation.

The FDA considered, and ultimately rejected, this option in its 2015 reassessment.

Groups like the Human Rights Campaign think that was the wrong decision.

“[We] support a model based on individual risk and a deferral period that reflects the actual time needed to detect HIV and other infectious diseases in the bloodstream,” Maril said. “The current proposed policy fails to meet the blood safety goals of the FDA and continues to exclude individuals solely because of their sexual orientation or gender identity.”

However, the FDA has recently opened their blood donor guidelines back up for comment, so Katz says his organization and others plan to work out a research protocol that should help answer some of these questions and provide the FDA with alternative strategies.

Still, with the uncertainty of funding and the complexities of designing and carrying out such research, Katz thinks the process will take years.

Read more: Researchers closer to HIV vaccine than ever before »

Fairness, not shortages

Advocates for a change in policy often cite blood shortages and the need for more donors.

But Katz said that’s not the real issue at hand.

“It ain’t about having enough blood,” he said. “It’s about following science, medicine, and fairness.”

Maril says the blood ban draws attention because it affects a broad swath of men across the country.

For many millennials who are turned away at blood banks, “This is the first sort of brush with discrimination that they might actually experience,” she said. “Looking at it on the individual level, it is a daily indignity and a daily experience of discrimination that further marginalizes a still vulnerable population.”