Have you ever had sex with a hemophiliac?
I know, during the 1970s a lot of hemophiliacs got HIV, and they are certainly a high risk group. But, since gay sex had been ruled out a few questions before this, this implies I would need to have slept with a female hemophiliac.
Female hemophiliacs are 1 in 100,000,000 and usually die at the onset of puberty. So not only would I have to scour the planet to find one, I would need to have sex with a prepubescent girl. Which by the way, would mean she was born in the late 1990s long after they fixed the blood supply that gave hemophiliacs HIV!
To answer yes to that question, would require pedophilia, crap loads of luck, and even then wouldn't imply any difference in safety.
Of less entertaining value they started calling Mad Cow Disease, "Mad Cow Disease." -- Apparently nobody knows what Creutzfeldt-Jakob disease is.