I actually had a brief discussion about this with the professor I was in Chiapas with. I am not legally able to donate blood because of the ban on male donors who have ever had sex with another man. The ban does not screen out heterosexual people who engage in high-risk behaviors, nor does it allow donations from non-heterosexual people who do not. Please be aware of the issue if you haven't been, and consider signing this petition.
https://www.credomobilize.com/petitions/tell-the-fda-end-the-ban-on-blood-donations-from-gay-men
https://www.credomobilize.com/petitions/tell-the-fda-end-the-ban-on-blood-donations-from-gay-men