I am going to refer back to Ms. Ballantyne's explanation. She explained that identifying some groups as being at especially high risk of these diseases is the result of very rigorous scientific studies that are widely accepted in our community. For example, those studies show that men who have had sexual relations with other men are, generally speaking, at the greatest risk of contracting HIV.
Again, this does not mean that a person in that group will necessarily be infected. That is not the issue. This is about identifying a group at risk. Men who have had sexual relations with other men are at risk. So are intravenous drug users. So are heterosexuals who have had sexual relations with people known to be at risk for HIV, whether they be men who have had sexual relations with other men or intravenous drug users.
These groups are deemed to be at higher risk. The other groups you refer to are at no higher risk than the general population. The basis on which the criteria have been established is a scientific, epidemiological one. The criteria apply to organ, cell and tissue donation just as they apply to blood donation.