I'm a regular blood donor, a Gold Card holder since I started donating since 3rd August 1977. I have seen the gradual tightening of the rules about who can donate. The biggest jump in tightening of the rules came in the 1980s (I can't remember which year exactly) when the HIV virus and AIDS were proven to be linked with homosexuality.
Today, you are not allowed to donate if you have had sex with another man only ONCE, nor having sex with a prostitute, or having had sex with someone from the Third World, taken drugs eg heroin, or if there is a family history of Hepatitis. One is temporary banned from donating if he had visited a Third World country without having sex, or if one just had an op, or received a transfusion himself, about to go down with a fever, visited a dentist within the last seven days (except for a routine check) or taken medicine within the last week before applying to donate, whether prescribed or not. There are other rules banning or restricting donations, but I'm in full support of these restrictions.
The truth is that a HIV virus, after infection, may remain dormant in the bloodstream for MANY YEARS without showing any symptoms that it's there. I for one has never had sex with another man, despite my orientation, therefore, I can donate, and here in the UK there is no reward payment for donors. And that with the fact that at every donation made, a small sample is taken to the lab to be tested for any signs of HIV and any other potential diseases.
If I was,or ever be a patient myself who must receive a transfusion as part of the treatment, it is assuring to know that the donated blood has passed the most stringent test before being declared fit for a transfusion.