Mayor Annise Parker brushed off her LGBT activist hat and lent her considerable political cred on Friday to a nationwide blood drive calling attention to a federal ban on gay male blood.

Parker even donated during the campaign's Houston event at a blood center in southwest Houston. Then she pointed her nearly 35,000 Twitter followers to a petition calling for an end to the federal government's longstanding ban on accepting blood donations from gay and bisexual men.

The event in Houston was one of 60 across the country calling attention to the ban, in place since 1983.

“To me this policy is not only discriminatory, but it also doesn't seem like the most effective way to keep the blood supply safe,” Emily Martin, an organizer of the Houston event, told Project Q last week. “It not only perpetuates the stigma that all gay men have HIV/AIDS, but it also dangerously promotes the idea that gay men are the only ones who have HIV/AIDS. Quite simply, I'm happy to do whatever I can to point that out and encourage what to me seems like a necessary change.”