The Orlando massacre that left 50 people dead and dozens wounded in a nightclub Sunday awakened compassion in some communities but provoked anger in others.

"Gay. Men. In. Orlando. Can't. Give. Blood. To. Their. Bleeding. Battered. Community. Dear @US_FDA, CHANGE THAT NOW," tweeted Brian Gerald Murphy, co-creator of Legalize Trans, a campaign that advocates for transgender people in the gay rights movement.

The Food and Drug Administration limits who can donate blood, asking questions of would-be blood donors such as, “Have you had sex with a man who has had sex with another man in the last year?”

If a man or woman answers yes, they cannot donate blood.

The FDA lists who can and cannot give blood on its website.

A partial ban on blood donated by gay men still exists, creating an irony where homosexuals might not be able to donate blood to save friends and family members.

But the original rule changed in December 2015 from a complete ban on blood from men who had ever had sex with another man. That complete ban started in 1983, when AIDS was recently discovered and scientists didn’t know enough about transmission or how to test blood for the disease.

While restrictions have loosened, the ban leaves many in the LGBT community without a way to donate blood.

Some early reports said OneBlood would accept gay blood donors, but that report turned out to be false, as OneBlood tweeted.

Donors are asked to make appointments to give blood later this week. OneBlood tweeted it was at capacity Sunday.