How is it fair that a gay man with one sexual partner in the last year is deferred, while a heterosexual man can have hundreds of sexual partners and isn’t?
It’s important to look at how statistical modelling is done. A straight man with hundreds of sexual partners would be a statistical anomaly (ie, very unusual). The projections are based on research about what happens across populations and the truth is that men who have sex with men (MSM) are far more likely to contract HIV during the course of their regular sex life than men who have sex with women.
Anomalies do exist but it is still reasonable to run statistical projections and assessments of risk based on general epidemiological data, rather than individual cases, when looking at the integrity of the blood supply. It’s these assessments that determine what questions the Blood Service asks of people seeking to make a donation.