A hidebound stigma? A "double tragedy?" US blood donation rules are coming under scrutiny after Sunday's mass shooting at a gay nightclub in Orlando.

After many who most wanted to show support for the massacre’s victims weren’t allowed to donate blood, critics are calling for a change to federal regulations that bar sexually active gay men from becoming blood donors.  

“I’m … hopeful that we can remove the ban that the FDA has on gay people donating blood,” Representative Jared Polis (D-Colorado) told local NBC affiliate KUSA on Sunday. 

“Many of the spouses and loved ones of the victims who need blood can’t even donate blood right now,” Polis said. “It’s just a double tragedy.”

The Food and Drug Administration requires people with a high risk of HIV infection to wait a year after a potential exposure to donate blood. That’s because the virus does not immediately show up in blood tests.  

The rule applies to men who have sex with men, recipients of blood transfusions, and many people who have recently gotten piercings or tattoos.

The one-year waiting period for all men who have had sex with men was instituted in December 2015, replacing a former life-long ban on blood donation from gay men.  

Some saw the rule change as a step forward for gay rights, but critics argue it still bears the shadows of stigma: the current policy excludes gay men in long-term monogamous relationships from giving blood, for example, but doesn’t bar heterosexual men who have multiple partners or unprotected sex.  

“It’s a distinction on paper which makes very little difference in reality,” said Brian Murphy, who works at Harlem United, a community health center in New York.

“Sexually active adults have sex. And so a one-year 'waiting period' amounts to a lifetime ban for most gay and bisexual men.”

The United States, like many countries, banned gay men from giving blood in the mid-1980s. Over the past 15 years, as HIV tests have gotten faster and infection trends have changed globally, many countries have reassessed their policies. 

The US instituted its 2015 change after a host of other countries moved away from an outright ban toward a waiting period, including Argentina, Australia, Brazil, Hungary, Japan, Sweden and the UK.

A year-long waiting period in Australia, the FDA said, 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.”

Many countries still ban gay men from donating blood altogether, but others are going even farther than the US and Australia toward inclusion.

Italy, for example, instituted an individualized risk assessment in 2001. A questionnaire handed out to all potential blood donors focuses on specific risky behaviors, including having unprotected sex and multiple partners, rather than homosexual activity. A 2013study found the policy change didn't have a significant impact on HIV prevalence in Italy.

Spain and South Africa also have individual risk assessments for potential blood donors, and activists are pushing for a similar policy in the US.  

But according to the FDA, there’s no scientific evidence that this approach would work in the United States, where the epidemiology of HIV and blood-testing methods are different than in the countries where it has already been instituted.

FDA spokesperson Tara Goodin wrote in an email that individual risk assessment “is a potential area for further research” and that immediate needs for blood donations following the Orlando nightclub shooting have been met.  

About two-thirds of all new HIV cases occur in men who have sex with men, a group that makes up only 2 percent of the total US population, according to data from the Centers for Disease Control and Prevention.

From PRI's The World ©2016 PRI